Computer documentation for Visual Basic.

87 Cunnings Visual Basic

Impactnetworking

87 Cunnings and tricks for Visual Basic.

Materials are kindly translated by Anton Minko

1. MANAGEMENT OF EVENTS

2. COMMENTING AND BLOCKS OF THE CODE

3. VALUES BY DEFAULT FOR UNESSENTIAL PARAMETERS

4. DO NOT CREATE ALIAS-ÍÛÕ VARIABLES

5. THE CENTERING OF THE FORM ON THE SCREEN

6. DO NOT TAKE A GREAT INTEREST FAST CODE

7. NOT ALL PATTERNS ARE CREATED EQUALLY

8. ADJUSTMENT IN VB

9. HOW TO HIDE ALL WINDOWS OF THE PROJECT

10. STANDALONE LIBRARIES OF TYPES

11. OBJECT BROWSER FOR THE FINDING NOT DOCUMENTARY PROBABLY

12. THE ADDRESS OF THE VARIABLE

13. WHEN BENCHMARK’è PROGRAMS LAST DAY

14. APP.PATH CAN RETURN UNC-ÏÓÒÈ

15. ABOUT UNIVERSAL PARAMETERS OF FILES

16. TO REDUCE THE SIZE OF THE CODE, USING OPERATORS IIF AND SWITCH

17. ACCELERATE YOUR CODE USE CHOOSE

18. GOSUBS WORK SLOWLY IN PROGRAMS

19. «ARRAY» - HENCEFORTH THIS ERRONEOUS NAME FOR VARIABLES

20. START AUTOMATION MANAGER AS HIDDEN PROBLEMS

21. PROBLEMS WITH EMERGING MENUS

22. USE OF THE COLLECTION FOR SELECTION OF UNIQUE VALUES

23. CREATION « FAR OFF CONTROLLABLE » FORMS

24. RECORD of the CURRENT POSITION And the SIZE of the FORM BY MEANS OF SAVESETT

25. The EFFECTIVE UTILIZATION INTERNAL VB CONSTANTS

26. THE CORRECT TEST ON " FILE EXIST "

27. THE PROCEDURES WORKING WITH GROUPS KONTROLOV

28. IMPROVEMENT OF FIGURES

29. THE CIPHERED PASSWORDS

30. CAPITAL-LOWER CASE LETTER - ADVICE ON TRACKING THE REGISTER

31. TRACKING DOUBLE CLICK FOR BUTTONS ON

32. VOLUME OF THE CATALOGUE

33. THE USEFUL DISK INFORMATION

34. PRESSING CTRL FOR ALLOCATION SEPARATE ITEM IN LIST

35. TO CHOOSE ALL FILES ON THE MASK

36. THE NAME OF THE CURRENT COMPUTER IN WINDOWS 95/NT

37. HOW TO SHOW FONTS WHEN YOU CHOOSE THEM

38. INTERCEPTION RIGHT UNITS TREEVIEW

39. START VB BY MEANS OF MENU SENDTO

40. NEW " HOT BUTTONS " FOR VB

41. HOW TO RECEIVE USERID UNDER WINDOWS 95/NT

42. The CONCLUSION of the SAND-GLASS DURING DATA PROCESSING

43. The ESTIMATION of the TIME INTERVAL (in minutes) BETWEEN TWO DATES

44. WILL SUFFICE TO PRINT!

45. TO CHANGE VALUES OF TWO VARIABLES

46. FAST MULTINOMINALS

47. FORMATTING AND COPYING OF DISKETTES THROUGH FUNCTIONS API

48. CONSECUTIVE NUMBERS OF VERSIONS

49. ALIGNMENT BY the RIGHT EDGE

50. VAL DOES NOT WORK ON THE FORMATTED NUMBERS

51. CLEVER GENERATOR ID

52. CHANGE OF THE SIZE OF DROPPING OUT AREA ON COMBOBOXE

53. QUANTITY of FREE MEMORY By means of WIN32

54. HOW OLD ARE YOU?

55. ABOUT WHICH IT IS IMPOSSIBLE TO FORGET

56. TO CREATE HURRIEDLY the FILE BY MEANS OF FUNCTION ARRAY

57. TO FIND CHOSEN IN FILE OPTION BUTTONS

58. PACKING VALUES CHECK-BOX IN ONE VARIABLE OF TYPE INTEGER

59. CONDITIONAL COMPILATION OF THE CODE

60. TO REDUCE BLINKING DURING LOADING the FORM

61. TO HIDE the INDEX ON CURRENT RECORD in DBGride

62. USE POP-UP THE MENU IN THE WINDOW WITHOUT TITLE BAR

63. HOW TO LEARN DIVIDERS OF DATE AND TIME WITHOUT FUNCTIONS API

64. PREVENTION OF MISTAKES AT USE GETSETTING

65. DUPLICATION OF LINES OF THE CODE WITHOUT SYNTACTIC MISTAKES

66. The LABEL FOR LOADING LAST EQUIPMENT DESIGN In VB

67. HOW TO DEDUCE the SYMBOL "and" In LABEL

68. CREATION OF TIME FILES

69. MOUSE EVENTS DO NOT HAPPEN IF ENABLE IS ESTABLISHED IN FALSE

70. HOW TO DEDUCE THE POPUP MENU ON TEXT BOXES

71. TO ALIGN the FORM In view

72. CLEARING THE LINE OF UNNECESSARY SYMBOLS

73. CHECK of OBJECTS BY MEANS OF TYPENAME

74. ADDITION OF THE LINE IN TEXT BOX

75. CHECK OF ARGUMENTS IN FUNCTION VAL

76. LABELS FOR INTERNET

77. VIEWING MAINTENANCE HELP-ÔÀÉËÀ

78. THE TASK OF BORDERS MDI OF THE FORM PRECISELY AS IN DESIGN-TIME

79. FAST SEARCH In the DATABASE

80. EASY TRACKING POSITION OF FOCUS

81. NOT CLOSED FORM

82. TO CHANGE PROPERTY TO THE WHOLE GROUP KONTROLOV

83. HOW SIMPLY TO FORMAT AND APPROXIMATE NUMBER

84. BE CAUTIOUS, HERE TO YOU NOT WITH!

85. TO USE BACKQUOTES INSTEAD OF APOSTROPHES

86. NEW VERSIONS OF THE PROGRAM ON THE NETWORK

87. TO CLOSE THE WINDOW OF THE PROGRAM AS IT DOES WINDOWS 95

1 MANAGEMENT OF EVENTS

Two problems can happen, when the confused user creeps COMBO by means of a mousy upwards and downwards, and then by pressing on Enter does the a choice. First, pressing on grey causes two events: Change and Click. Secondly, pressing on Enter moves focus to a following element of the form whereas pressing the button of the mouse does not cause similar effect (i.e. focus remains on COMBO). Therefore, if your code is placed in section of event Change on upwards/downwards (keyboard) will cause this event that you, naturally, do not want. On the contrary, if you place the code only in section of event Lost Focus and the user clicks the mouse on the choice focus will not leave from , and the user will behold the text which it has chosen the mouse, and to think, why it nothing occurs. The mentioned below decision « filters a market » events Click, generated pressing on keyboards, and compels to lose focus. In section Declarations of the form enter the following

' In VB3 it is necessary to change type of a flag on integer Dim bNoise as Boolean ' True means, that there is "noise" to which it is not necessary to react

And this code enter in section of event Form_Load:

bNoise = False

This code enter in event KeyDown Combo:

Private Sub cbTest_KeyDown (KeyCode As _ Integer, Shift As Integer) ' if the user uses arrows for driving under the list Combo/FONT> ' to ignore events Click If KeyCode = vbKeyDown Or KeyCode _ = vbKeyUp Then bNoise = True End Sub

This code is entered in event Click Combo:

Private Sub cbTest_Click () If bNoise Then ' Ignore Noise events ' (up or down arrow) bNoise = False Else ' To withdraw focus with SendKeys " {TAB} ", True End If End Sub

Now you need to write a code containing reaction to a choice of the user, and to bring it in section of event LostFocus Combo.

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2. COMMENTING AND BLOCKS OF THE CODE

VB5 Level: Beginning

VB 5.0 allows you the whole block of a code, and then also it is fast it. It is very useful at debugging when you do not need to execute a lot of operators, and at the same time you cannot remove them here and so simply for nothing. Meanwhile, the pair Comment/Uncomment is present only in òóëáàðå Edit which should be caused specially :-(. Quickly to cause òóëáàð Edit, click with the right button of the mouse on any òóëáàðå in VB, and choose then command Edit.

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3. VALUES BY DEFAULT FOR UNESSENTIAL PARAMETERS

VB5 Level: Beginning

If you ever ïðîãðàììèëè on VB4 you probably used a powerful chesspiece under the name Unessential parameters (Optional parameters). VB5 has gone further away: now these parameters can be any type (not only Variants), and can appear in procedures Property. It is interesting, that you can set now for them value by default.

Property Get Value _ (Optional index As Long = 1) End Property

You can do now it without was earlier obligatory (and terribly brake) by test IsMissing:

Property Get Value _ (Optional index As Long) If IsMissing (index) Then index = 1... End Property

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4. DO NOT CREATE ALIAS-ÍÛÕ VARIABLES

VB5 Level: Beginning

Never ïåðåäàâàéòe a global variable as argument in procedure which also directly addresses to this variable from itself (what for??). If you on 100 % are assured, that follow this rule in your programs cross out option Assume No Aliasing in dialogue window Advanced Optimizations which is caused from item Compile of dialogue Project Properties (óô, I hope, it is clear). If the compiler native code knows, that these most alias-th variables are not present, it easy copies values of variables in øóñòðûå registers ÖÏÓ, and copies their values back in RAM only at an output from procedure. It increases speed of execution of the compiled programs.

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5. THE CENTERING OF THE FORM ON THE SCREEN

VB5 Level: Beginning

Everyone know about small êîäèêå, allowing you to align the form on the screen without dependence from the graphic sanction. Now you can reach the same result, only having appropriated value vbStartUpScreen (=2) new property StartUpPosition of the form (has appeared in version 5). You even can center the form concerning its parental window, having appropriated value vbStartUpOwner (=1). Assignment can be made in window Property of the corresponding form. When you align the form inside of a parental window, do not forget to add the second argument in method Show.

Form2. Show vbModal, Me

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6. DO NOT TAKE A GREAT INTEREST ÀÂÒÎÎÏÒÈÌÈÇÈÖÈÅÉ FAST CODE

VB5 Level: Beginning

If to look at options native code optimization at first and washs away to click on " Optimize for Fast Code ". However, strangely enough it can sound, the given action far not always guarantees expected effect. Àïïëèêóõè, optimized on high-speed execution, as a rule, are not optimized (sorry for a pun), and only receive a lot of memory at loading. It addresses for them slower loading that is especially appreciable by machines with insufficient quantity RAM, and as a result makes impression, that you àïïëèêóõà works more slowly, rather than optimized under a compact code. For the same reason, consults êîìïèëèòü àïïëèêóõè in P-code. In case of volumetric, UI-and áàçîäàíñêèõ àïïëèêóõ, the prize from compilation in native-code at all will not move increase in the size àïïëèêóõè. In general, that precisely nobility, what compilation is necessary to you, þçàéòå VB Application Performance Explorer (APE) which lays on VB CD.

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7. NOT ALL PATTERNS ARE CREATED EQUALLY

VBA5 Level: Beginning

Unlike other products Office 97, patterns Word 97 contain business-application engine which is stored separately from documents, èñïîëüçþóùèõ this engine. Books Excel based on patterns and presentations PowerPoint store in themselves patterns on the basis of which they are created. In practice, all documents Word consist from 2õ VBA projects: the first project is created on the basis of the core (original, stored in Word) a pattern (all documents Word are based on patterns), and the second project belongs to document Word. On the other hand, books Excel and presentations PowerPoint created on patterns, contain only one VBA the project. Each file contains the own draft copy of an original pattern. The changes made in this pattern, do not mention the basic pattern stored the appendix.

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8. ADJUSTMENT ÒÓËÁÀÐÎÂ IN VB

VB5 Level: Beginning

Here some offers on adjustment IDE in VB5: To add bookmarks in òóëáîêñ it is possible, having cluck with the right button of the mouse on button General (that on òóëáîêñå), and having chosen Add Tab. You can move and delete also bookmarks, and move icons êîíòðîëîâ from one bookmark on another, using a usual method drag-and-drop. To pull out the button of any item of the menu on òóëáàð it is possible, having cluck with the right button on any òóëáàðå and having chosen item Customize. Pass to bookmark Commands, choose the necessary item of the menu in the right window, and drag it on òóëáàð. The first candidates on addition are items Project-References, Project-Properties, and Tools-Add Procedure. How to create absolutely new òóëáàð on âêëàäêå Toolbars dialogue window Customize. After you have defined contents of the future òóëáàðà, for addition of buttons on this òóëáàð use described by the paragraph above procedure. When at you on the screen dialogue window Customize is made active, click with the right button on any button òóëáàðà and you can change figure of the button, create a divider, hide/show the text, etc.

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9. HOW TO HIDE ALL WINDOWS OF THE PROJECT

VB5 Level: Beginning

When you work with several ïðåêòàìè at once, it is possible to get confused in a heap thuja õó÷è windows from different projects. However, you can temporarily hide all the windows concerning the given project, having clicked under the pictogram of the project in window Project Explorer so that all the branches which are sticking out of it, have disappeared. Then the windows concerning the given project will be curtailed also all. This opportunity can be cancelled, having clicked on ñîòâåòñòâóþùåì êâàäðàòèêå on bookmark General in menu Tools-Options.

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10. STANDALONE LIBRARIES OF TYPES

VB4 16/32, VB5 (Enterprise Edition) Level: Intermediate

Koãäà you create yours out-of-process OLE a server, VB builds in library of types of a server (companion type library) an EXE-file, not generating thus .TLB a file. However, if at you Enterprise Edition VB4 or VB5 having crossed out êâàäðàòèê Remote Server File, you will force VB to create standalone áèëèîòåêó types. In VB5, this option is on âêëàäêå Component dialogue window Properties menu Project.

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11. USE OBJECT BROWSER’a for a finding of not documentary opportunities

VB5 Level: Intermediate If to click with the right button of the mouse in right window Object Browser’à (there where members of classes are drawn) the contextual menu with command Show Hidden Members will jump out. If to click on this command, henceforth Object Browseráóäåò to show all hidden-properties and methods (together with classes) any library, and you can use it for more detailed research of libraries of objects. For example, in library VBA is hidden a class under the name _HiddenModule which includes many known functions VBA plus three not documentary: ObjPtr, StrPtr, and VarPtr. ObjPtr returns private area address of a copy of object, StrPtr returns the address first symbol in line, VarPtr returns the address of a variable or a descriptor of a line (string descriptor) if we have a case of a variable of type string.

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12. THE ADDRESS OF THE VARIABLE

VB4 16/32 Level: Advanced

In VB5 there is built in function VarPtr (see Advice « USE OBJECT BROWSER’a äëßíàõîæäåíèß not documentary opportunities »), but this function is not present in VB4. Runtime library in VB4 includes this function, but before its use it is necessary to declare all over again:

#If Win16 Then Declare Function VarPtr Lib "VB40016.DLL" (variable As Any) As Long #Else Declare Function VarPtr Lib "VB40032.DLL" (variable As Any) As Long #End If

This function is useful by transfer of the user types (Type structure) in external procedure API, and in this type any from fields is the address of other variable or record.

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13. WHEN BENCHMARK’è (MEASUREMENTS of SPEED of WORK of the PROGRAM) LAST DAY

VB4 16/32, VB5 Level: Intermediate

Usually, programmers on VB measure speed of performance of a code by means of Timer functions. However, if your program should come to the end next day you should consider, that the value returned by function Timer, ðåñåòèòñÿ at midnight. If you will accept value to within one second, you can simplify your code by means of function Now.

Dim startTime As Date StartTime = Now ' the code to be benchmarked '... Print " elapsedSeconds = " and Format $ ((Now - startTime) * 86400, "#####")

Function Format $ for a rounding off of result up to the whole is required to you.

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14. APP.PATH CAN RETURN UNC-ÏÓÒÈ

VB5 Level: Intermediate

Unlike VB4, App. Path in VB5 can return a UNC-way, type " \\ server \programs\... ", depending on circumstances, from that as the program is started and it from VB IDE is started or compiled in an EXE-file. This feature can strongly spoil to you a life if you use App. Path for installation of the current catalogue at start of the program.

ChDrive App. Path ChDir App. Path

As ChDrive on is able to process UNC-ways, this code can cause a fatal mistake of time of performance, but ìîæò to be protected by use On Error Resume Next. However this ôèêñ will not protect you from all íåâçãîä, able to occur. The best decision consists in that, ÷òîþû to give to the user most to enter the catalogue during execution of the program, then to write down the received way to the register or an INI-file. For more detailed èíôû, see clause Q167167 in Microsoft Knowledge Base.

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15 ABOUT UNIVERSAL PARAMETERS OF FILES

VB4 16/32, VB5 Level: Advanced you can write uniform procedure for any types of a file with any type as argument, using parameter of type Variant. Inside of procedure, addressing of elements of a file occurs in the usual way:

' return the number of items Function ItemCount (anArray As Variant) As Long ItemCount = UBound (anArray) - LBound (anArray) + 1 ' the first element is ' anArray (LBound (anArray)) End Function

You can even çàïóëèòü in procedure a multivariate file with any êîëè÷åñêòâîì measurements and to understand, how many at this file of measurements, it is necessary to make references to functions UBound and Lbound before occurrence of a mistake:

Function ItemCount (anArray As Variant) As Long Dim items As Long, i As Integer On Error Resume Next items = UBound (anArray) - LBound (anArray) + 1 For i = 2 to 999 items = items * (UBound (anArray, _ i) - LBound (anArray, i) + 1) If Err Then Exit For Next ItemCount = items End Function

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16. TO REDUCE THE SIZE OF THE CODE, USING OPERATORS IIF AND SWITCH

VB4 16/32, VB5 Level: Intermediate Often happens expedient to replace block If... Then... Else more compact function Iif:

' returns greater of two compared sizes maxValue = IIf (first> = second, first, second)

Switch - seldom used function, even in those numerous cases when it is more useful rather than the longest block If... ElseIf:

' it is necessary to learn, õ ïîëèæèòåëüíûé, negative, or it is equal 0? Print Switch (x <0, "negative", x> 0, _ "positive", True, "Null")

Let's notice, that value of last check always True as three conditions are mutually excluding and superfluous.

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17. ACCELERATE YOUR CODE USE CHOOSE

VB3, VB4 16/32, VB5 Level: Beginning

You can use Choose there where it is possible to replace a file or to construct tables of results, at a stage of compilation (compile-time), instead of doing it at a stage of performance (run time). For example, if you should know values of factorials of numbers from 1 up to 10, try a following example (Choose makes a choice of a factorial from a set of available values âñåñòî to calculate a factorial each time anew):

Function Factorial (number As Integer) _ As Long Factorial = Choose (number, 1, 2, 6, _ 24, 120, 720, 5040, 40320, _ 362880, 3628800) End Function

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18. GOSUBS WORK SLOWLY IN ÎÒÊÎÌÏÈËÈÐÎÂÀÍÍÛÕ PROGRAMS

VB5 Level: Intermediate

As use GoSubs concerns to not structured style of programming many programmers try to avoid it. If you compile yours VB5 àïïëèêóõó in native code, you will have one more reason to avoid this operator as calls through GoSubs can occur five times more slowly, than calls of usual procedure or function.

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19. «ARRAY» - HENCEFORTH THIS ERRONEOUS NAME FOR VARIABLES

VB5 Level: Intermediate

If you, as well as I, often use a name "array" for variables, you should reconsider your code at its carry under VB5. This word is now reserved (reserved keyword) and cannot be used as a name of a variable. You can easily alter your code by means of command Replace in IDE VB5, do not forget thus ÷åðêíóòü " Find whole words only ".

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20. START AUTOMATION MANAGER AS HIDDEN PROBLEMS

VB4 16/32, VB5 Enterprise Edition Level: Advanced

If you ìñïîëüçóåòå OLE Remote Automation, you should start in advance Automation Manager on a server before there will be the first OLE remote communication. By default, this appendix visible, but you can hide it, that it not ìîçîëèëî eyes on òàñêáàðå ×èêàãè. For this purpose create a label for Automation Manager which would include in a command line the switch/Hidden: C: \Windows \System \AutMgr32.Exe/Hidden On the other hand, you can change value of a corresponding key in the register. For fuller èíôû, see Clause Q138067 in the Microsoft Knowledge Base.

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21. PROBLEMS WITH EMERGING MENUS

VB4 16/32, VB5 Level: Advanced

If you use emerging menus (popup menus) in your programs be afraid of a bug which is available in VB4 16/32 and VB5. If you have two forms and one of them causes the second modal through the emerging menu from this the second modal you cannot cause any emerging menu, how many them on it was. That ïîôèêñèòü this business, use the timer on the first form. Instead of display ôòîðîé forms from the emerging menu on event Click, make active the timer so that it has shown this second form through some milliseconds. For fuller èíôû, see Clause Q167839 in the Microsoft Knowledge Base.

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22. USE OF THE COLLECTION FOR ÎÒÔÈËÜÒÐÎÂÛÂÀÍÈß THE DUPLICATED VALUES

VB4 16/32, VB5 Level: Intermediate This code illustrates how to use collections (Collection) for generation of a unique set of sizes from a set containing duplicates. In this example, the file of lines is scanned and are sorted all unique with use list-box êîíòðîëà:

Sub Remove_Duplicates (arr () As String) Dim i As Long Dim RawData As String Dim DataValues As New Collection

On Error Resume Next ' it is inserted for ignoring a mistake 457 - Duplicate key For i = LBound (arr) To UBound (arr) RawData = arr (i) DataValues. Add RawData, RawData ' If Run-time error 457 has happened, a repeating value is ignored Next On Error GoTo 0

' Preservation in List Box ' (property Sorted is exposed True) lstSortedData. Clear For Each DataValue In DataValues lstSortedData. AddItem DataValue Next End Sub

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23. CREATION « FAR OFF CONTROLLABLE » FORMS

VB3 Level: Intermediate

Sometimes it is required to me êîòðîëèðîâàòü one form when focus is on another. For example, when I press «ÎÊ» on the form And, I should make resize on the form of Century So, on each form which to me should « be supervised far off », I do invisible text box, we shall name it TextCommand, in event Change which there is a following code:

Sub TextCommand_Change () Dim msg as string msg = Trim $ (Me. TextCommand. Text) If Len (msg) = 0 Then Exit Sub

Select Case msg Case "COMMAND_RESIZE" Call MyFormResize Case "COMMAND_REPAINT" Call MyFormPaint... End Select Me. TextCommand = " " End Sub

You can supervise far off the form, transferring corresponding value in it TextCommand:

Sub Command1_Click () formB.TextCommand = "COMMAND_RESIZE" DoEvents End Sub

This code can be used for sending ìåññàãîâ from MDI forms to descendants:

Dim f As Form Set f = Me. ActiveForm f. TextCommand = "COMMAND_RESIZE"

If you sit under VB4 or VB5, you can use also Public-properties and methods of the form.

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24. RECORD of the CURRENT POSITION And the SIZE of the FORM BY MEANS OF SAVESETTING

VB4 16/32, VB5 Level: Intermediate Functions SaveSetting and GetSetting facilitate a writing ñåòòèíãîâ in àïïëèêóõàõ. These two functions restore and remember current positions of the form:

Public Sub FormPosition_Get (F As Form) ' Reads out a position of form F from ' ini/reg a file and accordingly ' positions form Dim buf As String Dim l As Integer, t As Integer Dim h As Integer, w As Integer Dim pos As Integer

buf = GetSetting (app. EXEName, _ "FormPosition", F.Tag, " ") If buf = " " Then ' defaults for a centering ôðîìû F.Move (Screen. Width - F.Width) \ _ 2, (Screen. Height - F.Height) \ 2 Else ' to allocate l, t, w, h and to expose the form pos = InStr (buf ",") l = CInt (Left (buf, pos - 1)) buf = Mid (buf, pos + 1) pos = InStr (buf ",") t = CInt (Left (buf, pos - 1)) buf = Mid (buf, pos + 1) pos = InStr (buf ",") w = CInt (Left (buf, pos - 1)) h = CInt (Mid (buf, pos + 1)) F.Move l, t, w, h End If End Sub

Public Sub FormPosition_Put (F As Form) ' Writes op, left, height and ' width positions of form F in reg/ini a file àïïëèêóõè Dim buf As String buf = F.left and "," and F.top and "," and _ F.Width and "," and F.Height SaveSetting app. EXEName, _ "FormPosition", F.Tag, buf End Sub

You should place these procedures in the module and to cause them from events Load and Unload forms. You should write a name of the form to its property Tag that these procedures worked correctly

Sub Form_Load () FormPosition_Get Me End Sub Sub Form_Unload () FormPosition_Put Me End Sub

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25. The EFFECTIVE UTILIZATION INTERNAL VB CONSTANTS

VB4 16/32, VB5 Level: Beginning

I had to see some advice on use of numerical values instead of corresponding VB constants. For example, you can deduce message box, using numerical constants:

rc = MsgBox (msg, 4 + 32 + 256, " Confirm Delete ")

Whether but not is easier prohonour the following?

rc = MsgBox (msg, vbYesNo + vbQuestion _ + vbDefaultButton2, _ " Confirm Delete ")

You can use following constants for check box:

VbUnchecked =0 VbChecked =1 VbGrayed =2

Also it is useful to know line constants instead of corresponding chr $ (symbols ASCII):

vbTab instead of Chr $ (9) vbCr instead of Chr $ (13) vbLf instead of Chr $ (10) vbCrLf instead of Chr $ (13) +Chr $ (10)

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26 THE CORRECT TEST ON " FILE EXIST "

VB3, VB4 16/32, VB5 Level: Intermediate

Dir $ generates runtime error if to it put a nonexistent name of a disk. For example, Dir $ ("d: \win \himems.sys") dies, if äðàéâ d: does not exist. For check of existence of a file, add îáðàáîò÷èê mistakes:

Function FileExist (filename As String) _ As Boolean On Error Resume Next FileExist = Dir $ (filename) <> " " If Err. Number <> 0 Then FileExist _ = False On Error GoTo 0 End Function

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27. THE PROCEDURES WORKING WITH GROUPS KONTROLOV

VB4 16/32, VB5 Level: Intermediate

You can use almost forgotten opportunity VB to have procedure or the function working with unlimited number of arguments that can be useful at work with set êîíòðîëîâ. For example, you can enable/disable group êîíòðîëîâ one call of procedure:

EnableAll True, Text1, Text2, _ Command1, Command2

This procedure passes on all êîíòðîëàì, transferred as arguments:

Sub EnableAll (Enabled As Boolean, _ ParamArray objs () As Variant) Dim obj As Variant For Each obj In objs obj. Enabled = Enabled Next obj End Sub

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28 IMPROVEMENT ÑÊÐÎËËÈÍÃÀ OF FIGURES

VB3, VB4 16/32, VB5 Level: Intermediate First, make, that event Scroll ñêðîëëáàðà pictures updated coordinates of a picture (as if it moves) when you carry ìûøîé on a picture. Then, declare following variables at a level of the form:

Dim StartX As Long, StartY As Long Dim Moving As Boolean

Finally, declare these three events for PicPicture: At last, declare this three events for PicPicture:

Private Sub PicPicture_MouseDown_ (Button As Integer, Shift As _ Integer, x As Single, y As Single) StartX = x StartY = y Moving = True End Sub

Private Sub PicPicture_MouseMove_ (Button As Integer, Shift As _ Integer, x As Single, y As Single) If Moving Then PicPicture. Move _ PicPicture. Left + x - StartX, PicPicture. Top + y - StartY End If End Sub

Private Sub PicPicture_MouseUp_ (Button As Integer, Shift As _ Integer, x As Single, y As Single) Moving = False End Sub

Now you can ñêðîëëèòü a picture ìûøîé. Do not forget to check up border of a picture.

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29. THE CIPHERED PASSWORDS

VB3, VB4 16/32, VB5 Level: Intermediate

Following two functions easily and effectively Þ¿õÓÒÔ/will decode the text password. Functions have two arguments: number from 1 up to 10 to shift a position of symbol ASCII in the password, and actually a line of the password. Function EncryptPassword passes through each symbol of line DecryptedPassword, checks a symbol on parity/oddness, and shifts it upwards/downwards according to parameter Number. This does the ciphered line not readable. The ciphered password «óêàòûâàåòñÿ» then operator XOR who even more confuses a line. I have limited parameter Number to number 10 as I should not do check on "wrong" symbols ASCII. Function DecryptPassword repeats upside-down process of enciphering, applying XOR, and then shift.

Function EncryptPassword (Number As _ Byte, DecryptedPassword As String) Dim Password As String, Counter As Byte Dim Temp As Integer

Counter = 1 Do Until Counter = _ Len (DecryptedPassword) + 1 Temp = Asc (Mid (DecryptedPassword, _ Counter, 1)) If Counter Mod 2 = 0 Then ' see if even Temp = Temp - Number Else Temp = Temp + Number End If Temp = Temp Xor (10 - Number) Password = Password and Chr $ (Temp) Counter = Counter + 1 Loop EncryptPassword = Password End Function

Function DecryptPassword (Number As _ Byte, EncryptedPassword As String) Dim Password As String, Counter As Byte Dim Temp As Integer

Counter = 1 Do Until Counter = _ Len (EncryptedPassword) + 1 Temp = Asc (Mid (EncryptedPassword, _ Counter, 1)) Xor (10 - Number) If Counter Mod 2 = 0 Then ' see if even Temp = Temp + Number Else Temp = Temp - Number End If Password = Password and Chr $ (Temp) Counter = Counter + 1 Loop DecryptPassword = Password End Function

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30. CAPITAL-LOWER CASE LETTER - ADVICE ON TRACKING THE REGISTER OF LETTERS

VB4 16/32, VB5 Level: Intermediate If you use the left arrow on êëàâå to pass to the beginning of a word, and then press the letter as a result you receive two header letters (the first already was, and the second was entered by you - I so understand??). Having applied a code, which uses advantages built in in VB4/VB5 functions StrConv (), you receive automatic reduction of letters the necessary register during input:

Private Sub Text1_Change () If Text1. Tag = " " Then Text1. Tag = Text1. SelStart Text1. Text = StrConv (Text1. Text, vbProperCase) Text1. SelStart = Text1. Tag Text1. Tag = " " End If End Sub

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31. TRACKING DOUBLE CLICK FOR BUTTONS ON ÒÓËÁÀÐÅ

VB4 32, VB5 Level: Intermediate VB4 supports built in in Win95 êîíòðîë Toolbar, allowing users to add buttons on Òóëáàð. These buttons have event ButtonClick but if you wish to catch double-click standard event ButtonDoubleClick is not present. To correct it, declare two variables of a level of the form:

Private mbSingleClicked As Boolean Private mbDoubleClicked As Boolean

In the Toolbars ButtonClick event, add this code: In event ButtonClick Òóëáàðà add a following code:

Private Sub Toolbar1_ButtonClick_ (ByVal Button As Button) Dim t As Single t = Timer If mbSingleClicked = True Then mbDoubleClicked = True MsgBox " Double Clicked " Else mbSingleClicked = True ' to allow the user to click once again if it wants double-click Do While Timer - t <1 And mbSingleClicked = True DoEvents Loop ' if the user has made DoubleClick, to leave procedure If mbDoubleClicked = True Then mbSingleClicked = False mbDoubleClicked = False Exit Sub End If End If If mbDoubleClicked = False Then MsgBox " Single Clicked " End If

' an example of processing of these events ' If mbDoubleClicked Then '---------code ' ElseIf mbSingleClicked Then '---------code ' End If

' at an output from procedure it is necessary ðåèíèòèòü variables, differently we shall rest in SingleClickè If mbDoubleClicked = False Then mbSingleClicked = False mbDoubleClicked = False End If End Sub

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32. VOLUME OF THE CATALOGUE IN ÁÀÉÒÀÕ

VB3, VB4 16/32, VB5 Level: Intermediate

This function returns number of the bytes borrowed by files in the catalogue:

Function DirUsedBytes (ByVal dirName As _ String) As Long Dim FileName As String Dim FileSize As Currency

' to add \ if was not If Right $ (dirName, 1) <> "\" Then dirName = dirName and "\" Endif FileSize = 0 FileName = Dir $ (dirName and " *. * ")

Do While FileName <> " " FileSize = FileSize + _ FileLen (dirName and FileName) FileName = Dir $ Loop DirUsedBytes = FileSize

End Function

Example of a call of such function:

MsgBox DirUsedBytes ("C: \Windows")

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33. THE USEFUL DISK INFORMATION

VB4 32, VB5 Level: Advanced

This function returns quantity of free space on a disk, total amount of a disk, a share of free space í àäèñêå, and èñïîëüçâàííîå space. Before a call of function, appropriate to the first field of structure DISKSPACEINFO ("RootPath") a name of a disk:

Dim dsi As DISKSPACEINFO dsi. RootPath = " C: \ " GetDiskSpace dsi

Function returns all results in other fields of record (structure):

' *** Declaratiosn Section ****** Declare Function GetDiskFreeSpace Lib _ "kernel32" Alias _ "GetDiskFreeSpaceA" _ (ByVal lpRootPathName As String, _ lpSectorsPerCluster As Long, _ lpBytesPerSector As Long, _ lpNumberOfFreeClusters As Long, _ lpTotalNumberOfClusters As Long) _ As Long

Type DISKSPACEINFO RootPath As String * 3 FreeBytes As Long TotalBytes As Long FreePcnt As Single UsedPcnt As Single End Type

' ****** THE MODULE OF THE CODE ****** Function GetDiskSpace (CurDisk As _ DISKSPACEINFO) Dim X As Long Dim SxC As Long, BxS As Long Dim NOFC As Long, TNOC As Long

X& = GetDiskFreeSpace_ (CurDisk. RootPath, SxC, BxS, _ NOFC, TNOC) GetDiskSpace = X&

If X& Then CurDisk. FreeBytes = BxS * _ SxC * NOFC CurDisk. TotalBytes = BxS * _ SxC * TNOC CurDisk. FreePcnt = ((CurDisk._ TotalBytes CurDisk._ FreeBytes) / CurDisk._ TotalBytes) * 100 CurDisk. UsedPcnt = _ (CurDisk. FreeBytes / _ CurDisk. TotalBytes) * 100 Else CurDisk. FreeBytes = 0 CurDisk. TotalBytes = 0 CurDisk. FreePcnt = 0 CurDisk. UsedPcnt = 0 End If End Function

In such kind, function works with äðàéâàìè the size somewhere up to 2Ãá, for greater disks it is necessary to use variables of type Single.

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34. AS ÑÛÌÈÒÈÐÎÂÀÒÜ PRESSING OF KEY CTRL FOR ALLOCATION OF UNTIED PIECES IN LIST BOX

VB4 32, VB5 Level: Advanced

When property MultiSelect usual listboxà is established in 1 - Simple or in 2 - Extended, the user should press Ctrl at êëèêàíèè inside of it listboxà to allocate untied (going íåïîäðÿä) elements. My method allows the user to choose some elements, not pressing thus Ctrl. Place a mentioned below code in the module.

Declare Function GetKeyboardState Lib _ "user32" (pbKeyState As Byte) _ As Long Declare Function SetKeyboardState Lib _ "user32" (lppbKeyState As Byte) _ As Long Public Const VK_CONTROL = &H11 Public KeyState (256) As Byte

This code thrust in event MouseDown of yours listboxà (we shall name it List1) at which property MultiSelect is established in Simple or Extended:

' "presses" Ctrl GetKeyboardState KeyState (0) KeyState (VK_CONTROL) = _ KeyState (VK_CONTROL) Or &H80 SetKeyboardState KeyState (0)

This code place in procedure in which it is necessary "to wring out" Ctrl, for example, List1_LostFocus:

' "wrings out" Ctrl GetKeyboardState KeyState (0) KeyState (VK_CONTROL) = _ KeyState (VK_CONTROL) And &H7F SetKeyboardState KeyState (0)

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35. TO CHOOSE ALL FILES ON THE MASK IN ÏÎÄÄÅÐÅÂÅ CATALOGUES

VB3, VB4 16/32, VB5 Level: Intermediate

As this code does not use API, you can easily transfer it with 16 on a 32-bit platform and back. Procedure DirWalk ïîçâîäèò to you to see all ïîääåðåâî, since çàäàíííîãî places:

ReDim sArray (0) As String Call DirWalk ("OLE*.DLL", " C: \ ", sArray)

This procedure accepts * and? In the first argument which sets a mask of search. You can set some masks, dividing their symbol «;», for example, " OLE*.DLL; *.TLB ". The second argument - a place of start, the third argument - a file of lines. This procedure recursively passes under all catalogues and puts all the files, satisfying to a condition, in a file sArray with the instruction of a full way. This file changes the sizes depending on quantity of the files, satisfying to conditions of search. For èñïîëüçîâíèÿ DirWalk, push two êîíòðîëà, FileListBox and DirListBox, on the form. This procedure means, that it works with êîíòðîëàìè on the current form:: FileListBox by name File1, and DirListBox by name Dir1. For increase in speed of work make these êîíòðîëû invisible. Use of these êîíòðîëîâ does not demand purchase additional òóëçîâ as they (êîíòðîëû) contain in base library êîíòðîëîâ VB.

Sub DirWalk (ByVal sPattern As String, _ ByVal CurrDir As String, sFound () _ As String) Dim i As Integer Dim sCurrPath As String Dim sFile As String Dim ii As Integer Dim iFiles As Integer Dim iLen As Integer

If Right $ (CurrDir, 1) <> "\" Then Dir1. Path = CurrDir and "\" Else Dir1. Path = CurrDir End If For i = 0 To Dir1. ListCount If Dir1. List (i) <> " " Then DoEvents Call DirWalk (sPattern, _ Dir1. List (i), sFound ()) Else If Right $ (Dir1. Path, 1) = "\" _ Then sCurrPath = Left (Dir1. Path, _ Len (Dir1. Path) - 1) Else sCurrPath = Dir1. Path End If File1. Path = sCurrPath File1. Pattern = sPattern If File1. ListCount> 0 Then ' the necessary files are found in catalogue For ii = 0 To File1._ ListCount - 1 ReDim Preserve _ sFound (UBound (sFound) _ + 1) sFound (UBound (sFound) - _ 1) = sCurrPath and _ "\" and File1. List (ii) Next ii End If iLen = Len (Dir1. Path) Do While Mid (Dir1. Path, iLen, _ 1) <> "\" iLen = iLen - 1 Loop Dir1. Path = Mid (Dir1. Path, 1, _ iLen) End If Next i End Sub

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36. THE NAME OF THE CURRENT COMPUTER IN WINDOWS 95/NT

VB4 32, VB5 Level: Advanced

Often you should know a name of a current computer under WINDOWS 95/NT from yours VB programs. Use this unpretentious function API from kernel32.dll:

Private Declare Function GetComputerNameA Lib "kernel32" _ (ByVal lpBuffer As String, nSize _ As Long) As Long

Public Function GetMachineName () As _ String Dim sBuffer As String * 255 If GetComputerNameA (sBuffer, 255&) _ <> 0 Then GetMachineName = Left $ (sBuffer, _ InStr (sBuffer, vbNullChar) _ - 1) Else GetMachineName = " (Not Known) " End If End Function

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37. HOW TO SHOW FONTS WHEN YOU CHOOSE THEM

VB3, VB4 16/32, VB5 Level: Intermediate That the user could change a name of a font, load all fonts in êîìáîáîêñ:

Private Sub Form_Load () ' to define quantity of screen fonts. For I = 0 To Screen. FontCount - 1 ' to thrust all fonts in ëèñòáîêñ. cboFont. AddItem Screen. Fonts (I) Next I End Sub

Decorate procedure, having allowed the user at once to see result of the choice, needlessly to print "something" as the test:

Private Sub cboFont_Click () ' to make chosen FontName a font combobox cboFont. FontName = cboFont. Text End Sub

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38. INTERCEPTION RIGHT ÊËÈÊÎÂ ON UNITS TREEVIEW

VB4 32, VB5 Level: Intermediate

Êîíòðîë TreeView gives to yours àïïëèêóõå finished kind Windows 95. However, in textbooks on VB it is not told how to intercept right mouse cliques on unit (node) a tree. Event Treeview_MouseDown occurs before event NodeClick. To show the contextual menu above unit, use this code and define a key (Key) for for each unit in the form of the letter and number following it.

+ Root (R01) ' the letter gives | ---Child 1 (C01) ' the indication to | - + Child 2 (C02) ' the context menu | | ---Child 2.1 (H01) | | ---Child 2.2 (H02)

Dim bRightMouseDown as Boolean

Private Sub Form_Load () bRightMouseDown = False End Sub

Private Sub treeview1_MouseDown_ (Button As Integer, Shift As _ Integer, X As Single, Y As Single) If Button And vbRightButton Then bRightMouseDown = True Else bRightMouseDown = False End If End Sub

Private Sub treeview1_MouseUp_ (Button As Integer, Shift As _ Integer, X As Single, Y As Single) bRightMouseDown = False End Sub

Private Sub treeview1_NodeClick_ (ByVal Node As Node) Select Case Left (Node. Key, 1) Case "R" If Not bRightMouseDown Then ' do the normal node click, ' so you must here the code ' for the node code click Else ' a choice of unit treeview1. Nodes (Node. Key) .Selected = True ' to show contextual menu PopupMenu mnuContext1 End If Case "C" If Not bRightMouseDown Then ' do the normal node click, ' so you must here the code ' for the node code click Else ' a choice of unit treeview1. Nodes (Node. Key) .Selected = True ' to show contextual menu PopupMenu mnuContext2 End If

' the same with other units '.... End Select End Sub

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39. START VB BY MEANS OF MENU SENDTO

VB3, VB4 16/32, VB5 Level: Intermediate Addition of a label " Shortcut to VB.exe " and " Shortcut to VB32.exe " in the menu " Send To " allows you right-clickîì on any VBP the project to open it in VB4 16/32 or in VB5 - on a choice. Come into yours VB the catalogue, right-clickíèòå on VB32.exe, and choose " Create shortcut. ". When the label will be created, move it to catalogue C: \Windows \Sendto. Now at right-clickå on the project you can choose where "to send" your project. You can add labels for WordPad, Word, Excel or any other program supposing use of an entrance file as parameter of start.

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40. NEW “ HOT BUTTONS ” FOR VB

VB4 16/32, VB5 Level: Intermediate

1) In VB5, press Ctrl-F3 when the cursor is above any word. Thus following ocurrence of this word will be automatically found in the text, passing dialogue of search. The cursor should stand at least behind the first letter of a word that this feature worked correctly.

2) In VB4/5 pressing Ctrl-Tab it is possible to move between all open windows in IDE, it often appears more quickly, than to go to menu Window.

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41. HOW TO RECEIVE USERID UNDER WINDOWS 95/NT

VB4 32, VB5 Level: Intermediate

Often you should receive userID the current user working with your program. Use for this purpose updating of one of functions API:

Option Explicit

Private Declare Function WNetGetUserA _ Lib "mpr" (ByVal lpName As String, _ ByVal lpUserName As String, _ lpnLength As Long) As Long

Function GetUser () As String Dim sUserNameBuff As String * 255 sUserNameBuff = Space (255) Call WNetGetUserA (vbNullString, _ sUserNameBuff, 255&) GetUser = Left $ (sUserNameBuff, _ InStr (sUserNameBuff, _ vbNullChar) - 1) End Function

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42 CONCLUSION of the SAND-GLASS DURING DATA PROCESSING

VB4 32, VB5 Level: Advanced

Íèæåóêàçàííàÿ the technique simplifies switching MousePointerà, without addition ñïåö. A code in the end of each procedure/function. When you ñîçàäåòå the object from any class, is generated event Initialize. Then the code of corresponding procedure is executed. It is the first code executed for given object, it is executed before assignment of any properties to object and before performance of methods of object. When the variable leaves area of visibility, all references to object are destroyed, and the code for event Terminate is carried out.

Declare Sub Sleep Lib "kernel32" _ (ByVal dwMilliseconds As Long)

' the example of the procedure using class CHourGlass Private Sub ProcessData () Dim MyHourGlass As CHourGlass Set MyHourGlass = New CHourGlass ' here is inserted a code of data processing Sleep 5000 ' It models data processing ' continuation of code End Sub

' creation of class CHourGlass: Private Sub Class_Initialize () ' To show HourGlass Screen. MousePointer = vbHourglass End Sub

Private Sub Class_Terminate () ' To restore MousePointer Screen. MousePointer = vbDefault End Sub

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43. The ESTIMATION of the TIME INTERVAL (in minutes) BETWEEN TWO DATES

VB4 16/32, VB5 Level: Beginning the number of the last minutes between two events can be necessary for you. A code:

lTotalMinutes = Minutes (Now) - _ Minutes (datStartTime)

This function returns quantity of minutes with 01/01/1900:

Public Function Minutes (d As Date) _ As Long ' the Minutes which have been last with 1900 Dim lPreviousDays As Long Dim lTotalMinutes As Long

lPreviousDays = d - #1/1/1900# lTotalMinutes = _ (lPreviousDays * 24) * 60 lTotalMinutes = lTotalMinutes + _ Hour (d) * 60 lTotalMinutes = lTotalMinutes + _ Minute (d)

Minutes = lTotalMinutes End Function

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44. WILL SUFFICE TO PRINT!

VB3, VB4 16/32, VB5 Level: Beginning

Sometimes to me the line after line would be desirable to unpack data from recordsetà. However, it is difficult enough ïðêðàòèòü this process before all recordset will leave in turn of the printer. Use button Cancel which establishes a flag. Except for the button sending the task for a press, create one more, under name Cancel. You also can appropriate to its property Cancel value True that the user could stop a press pressing on Esc. Add one more variable in the module:

Dim CancelNow As Integer

Put this code in the Click event of the Cancel button: Add this code in event Click of button Cancel:

Sub cCancel_Click () CancelNow =-1 DoEvents End Sub

You can even do without the button and catch only pressing on Escape. In this case, establish property KeyPreview of the form in True and insert a following code:

Sub Form_KeyPress (KeyAscii As Integer) ' if the user presses ESC If KeyAscii = (27) Then CancelNow =-1 DoEvents End If End sub

At last, insert check of a flag inside of a cycle of a press:

'... Any code... ' a press recordset from database Do While Not MyRecordSet. EOF Printer. Print MyRecordSet! SomeRecord MyRecordSet. MoveNext DoEvents ' a stop if has been pressed Cancel If CancelNow then Exit Do Loop Printer. EndDoc '... A code further...

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45. TO CHANGE VALUES OF TWO VARIABLES

VB3, VB4 16/32, VB5 Level: Intermediate

Use this algorithm to swap two integer variables: Actually, here:

a = a Xor b b = a Xor b a = a Xor b

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46. FAST ÎÁÑ×ÅÒ MULTINOMINALS

VB3, VB4 16/32, VB5 Level: Intermediate

Well-known formula Ãîðíåðà allows to consider quickly ïîëèíîìèàëüíûå expressions. To count A*x^N + B*x (N-1) + … + Y*x + Z (means a degree), write: (… ((A*x + B) *x + C) *x + … +Y) *x + Z.

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47. FORMATTING AND COPYING OF DISKETTES THROUGH FUNCTIONS API

VB4 32, VB5 Level: Advanced

In Win32 API there is a couple of the functions, allowing to format and copy diskettes from the program:

Private Declare Function SHFormatDrive _ Lib "shell32" (ByVal hwnd As Long, _ ByVal Drive As Long, _ ByVal fmtID As Long, _ ByVal options As Long) As Long Private Declare Function GetDriveType _ Lib "kernel32" _ Alias "GetDriveTypeA" _ (ByVal nDrive As String) As Long

Add two command buttons in the form, name them cmdDiskCopy and cmdFormatDrive, and thrust in their events Click following fragments of a code:

Private Sub cmdDiskCopy_Click () ' DiskCopyRunDll demands two parameters - From and To Dim DriveLetter $, DriveNumber&, _ DriveType& Dim RetVal&, RetFromMsg& DriveLetter = UCase (Drive1. Drive) DriveNumber = (Asc (DriveLetter) - _ 65) DriveType = GetDriveType_ (DriveLetter) If DriveType = 2 Then ' Floppies, _ etc RetVal = Shell_ ("rundll32.exe" and _ " diskcopy.dll, " _ and "DiskCopyRunDll" and _ DriveNumber and "," and _ DriveNumber, 1) Else ' Just in case RetFromMsg = MsgBox_ (" Only floppies can be " and _ "copied", 64, _ " DiskCopy Example ") End If End Sub

Private Sub cmdFormatDrive_Click () Dim DriveLetter $, DriveNumber&, _ DriveType& Dim RetVal&, RetFromMsg % DriveLetter = UCase (Drive1. Drive) DriveNumber = (Asc (DriveLetter) - _ 65) ' To replace the letter with figure: A=0 DriveType = GetDriveType_ (DriveLetter) If DriveType = 2 Then _ ' i.e. ôëîï RetVal = SHFormatDrive (Me.hwnd, _ DriveNumber, 0&, 0&) Else RetFromMsg = MsgBox_ (" This drive is NOT a " and _ " removeable drive! " And _ " Format this drive? ", _ 276, " SHFormatDrive Example ") If RetFromMsg = 6 Then ' Ðàñêîììåíòèðóéòå also will see... ' RetVal = SHFormatDrive_ (Me.hwnd, _ ' DriveNumber, 0&, 0&) End If End If End Sub

Add êîíòðîë DriveListBox under name Drive1:

Private Sub Drive1_Change () Dim DriveLetter $, DriveNumber&, _ DriveType& DriveLetter = UCase (Drive1. Drive) DriveNumber = (Asc (DriveLetter) - _ 65) DriveType = GetDriveType_ (DriveLetter) If DriveType <> 2 Then _ ' Floppies, etc cmdDiskCopy. Enabled = False Else cmdDiskCopy. Enabled = True End If End Sub

Be cautious: so it is short also the screw çàïîðîòü.

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48. CONSECUTIVE NUMBERS OF VERSIONS

VB4 16/32, VB5 Level: Intermediate

For tracking sequence of versions, use this procedure if you use number of the version:

Public Function GetMyVersion () As String ' converts number of the version in something like "2/1/0001" Static strMyVer As String If strMyVer = " " Then strMyVer = Trim $ (Str $ (App. Major)) and "." And _ Format $ (App. Minor, "##00") _ and "." Format $ (App. Revision, "000") End If GetMyVersion = strMyVer End Function

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49. ALIGNMENT ÊÎÍÒÐÎËÎÂ BY the RIGHT EDGE

VB3, VB4 16/32, VB5 Level: Beginning

At creation of forms with the unstable sizes, I prefer to place all êîíòðîëû in right bottom and right top corners. For example, on forms where data are entered, I put buttons of navigation on records in the left bottom part of the form together with buttons Add New Record, Delete Record, and Find Record. In the bottom right corner I put buttons print preview and closings of the form. Place this procedure in the module or general declarations forms. In parameter Offset you can change a distance from a right edge of the form, that is you can level by a right edge yours êîíòðîëû.

Sub ButtonRight (X As Control, _ Frm As Form, Offset as Integer) X.Left = Frm. ScaleWidth - _ X.Width - Offset End Sub

Place two command buttonà on the form. In event Form_Resize, add about such code:

Private Sub Form_Resize () ButtonRight Command1, Me, 0 ButtonRight Command2, Me, _ Command1. Width End Sub

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50. VAL () DOES NOT WORK ON THE FORMATTED NUMBERS

VB3, VB4 16/32, VB5 Level: Intermediate

More cautiously with function Val (). It incorrectly distinguishes the formatted numbers. Use instead of it CInt (), CDbl ().

FormattedString = Format (1250, _ "General") ' = " 1,250.00" Debug. Print Val (FormattedString) ' will print 1! Debug. Print cDbl (FormattedString) ' will print 1250

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51. CÌÛØËÅÍÛÉ GENERATOR ID

VB3, VB4 16/32, VB5 Level: Intermediate

I have written the generator for creation unique íîìèðîâ, type of number àêàóíòà, or ID in âàøåè the appendix. I use it together with ôåíêöèåé CheckForValid, for example CheckForValid will return True for number "203931." And will return False for "209331."

Function CheckForValid (Num As Long) _ As Boolean ' Check for valid number Result = Num Mod 13 If Result <> 0 Then CheckForValid = False ' if false then the number is wrong Else CheckForValid = True ' if true the number is OK End If End Function

Function Generate (Num As Long) As Long ' Generates the successor of a valid ' number If CheckForValid (Num) Then Generate = Num + 13 ' if valid Generate Else Generate =-1 ' Otherwise return-1 End If End Function

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52. CHANGE OF THE SIZE OF DROPPING OUT AREA ON COMBOBOXE

VB4 32, VB5 Level: Advanced In VB there is no property ListRows i.e. if you should represent more than 8 äåôîëòîâûõ lines on the dropping out list comboboxà use this procedure for increase in the size of a window comboboxà:

Option Explicit

Type POINTAPI x As Long y As Long End Type

Type RECT Left As Long Top As Long Right As Long Bottom As Long End Type

Declare Function MoveWindow Lib _ "user32" (ByVal hwnd As Long, _ ByVal x As Long, ByVal y As Long, _ ByVal nWidth As Long, _ ByVal nHeight As Long, _ ByVal bRepaint As Long) As Long Declare Function GetWindowRect Lib _ "user32" (ByVal hwnd As Long, _ lpRect As RECT) As Long Declare Function ScreenToClient Lib _ "user32" (ByVal hwnd As Long, _ lpPoint As POINTAPI) As Long

Public Sub Size_Combo (rForm As Form, _ rCbo As ComboBox) Dim pt As POINTAPI Dim rec As RECT Dim iItemWidth As Integer Dim iItemHeight As Integer Dim iOldScaleMode As Integer

' Change Scale Mode of the form on Pixels iOldScaleMode = rForm. ScaleMode rForm. ScaleMode = 3 iItemWidth = rCbo. Width

' Installation of new height comboboxà iItemHeight = rForm. ScaleHeight - rCbo. Top - 5 rForm. ScaleMode = iOldScaleMode

' Reception of coordinates in relation to screen Call GetWindowRect (rCbo.hwnd, rec) pt.x = rec. Left pt.y = rec. Top

' then coordinates in the form of Call ScreenToClient (rForm.hwnd, pt)

' Change of the size comboboxà Call MoveWindow (rCbo.hwnd, pt.x, _ pt.y, iItemWidth, iItemHeight, 1) End Sub

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53. QUANTITY of FREE MEMORY By means of WIN32

VB4 32, VB5 Level: Advanced

If you should be shown users, how many free memory is accessible by the machine, and you send with 16áèò on 32 bats a platform you sweep up, that function API GetFreeSystemResources èñÿåçëà. But it it doesn't matter. You should declare only API function and following type in the module:

Declare Sub GlobalMemoryStatus Lib _ "kernel32" (lpBuffer As _ MEMORYSTATUS)

Type MEMORYSTATUS dwLength As Long dwMemoryLoad As Long dwTotalPhys As Long dwAvailPhys As Long dwTotalPageFile As Long dwAvailPageFile As Long dwTotalVirtual As Long dwAvailVirtual As Long End Type

Bring in a floor dwlength the size of type MEMORYSTATUS. The variable of type Long takes 4 áàéòà so all will leave 4*8=32 áàéòà:

Dim ms As MEMORYSTATUS

ms.dwLength = Len (ms) GlobalMemoryStatus ms MsgBox " Total physical memory: " both _ ms.dwTotalPhys and vbCr _ and " Available physical memory: " both _ ms.dwAvailPhys and vbCr and _ " Memory load: " and ms.dwMemoryLoad

You can even write a class, in which èíêàïñóëèðîâàòü all above-stated.

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54. HOW OLD ARE YOU?

VB5 Level: Intermediate

This function returns a difference between two dates in years, months and days:

Function GetAge (dtDOB As Date, _ Optional dtDateTo As Date = 0) _ As String ' dtDateto it is transferred? If dtDateTo = 0 Then dtDateTo = Date End If GetAge = Format $ (dtDateTo - _ dtDOB, " yy - mm - dd ") End Function

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55. ÓÇÅËÎÊ ABOUT WHICH IT IS IMPOSSIBLE TO FORGET

VB3, VB4 16/32, VB5 Level: Intermediate

I often work above several projects simultaneously. Jumping from one project on another and back, sometimes I lose a trace, in what program in what place I have stopped. For the decision of this problem, take and print any phrase without inverted commas of the comment. Next time, when you start the project, choose item " Start With Full Compile ". If this phrase will be the first mistake in the project, you at once will see its illuminated and your memory will be freshened.

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56. TO CREATE HURRIEDLY the FILE BY MEANS OF FUNCTION ARRAY

VB4 16/32, VB5 Level: Intermediate

Method GetRows copies lines Recordsetà (JET) or rdoResultsetà (RDO) in a file. I often use this feature for data transmission between OLE Serverîì and client àïïëèêóõàìè. This method uses a variable of type Variant as parameter for storage of returned data. It is a bidimentional file (on internal representation VB)

Dim A As Variant A = Array (10,2)

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57. TO FIND CHOSEN ÊÎÍÒÐÎË IN FILE OPTION BUTTONS

VB4 16/32, VB5 Level: Intermediate Use this code for a finding of an index chosen êîíòðîëà from a file option buttons

Function WhichOption (Options As _ Object) As Integer

' This function returns index Option Button, whose value true.

Dim i ' If Options - not that object, or not the object in general On Error GoTo WhichOptErr ' Default to failed WhichOption =-1 ' checks everyone OptionButton in a file. I ask to note, that function gives out ' wrong value if indexes go not successively For i = Options.lbound To _ Options.ubound If Options (i) Then ' to remember value of found index WhichOption = i ' and to leave Exit For End If Next WhichOptErr:

End Function

Consider, that iCurOptIndex has type integer, and Option1 this name of a file êîíòðîëîâ OptionButton.

iCurOptIndex = WhichOption (Option1)

Important: parameter of function - object. It will work only with parameters-objects or type variant.

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58. PACKING VALUES CHECK-BOX IN ONE VARIABLE OF TYPE INTEGER

VB4 16/32, VB5 Level: Intermediate

Using a following code, it is possible to deduce binary representation çà÷åðêíóòûõ check boxîâ:

Function WhichCheck (ctrl As Object) As _ Integer ' This function returns binary representation of a file êîíòðîëîâ, ' where everyone çà÷åðêíóòûé ÷åêáîêñ is represented the two in a degree of the index in ' a file, íàïð.ýëåìåíò 0 : 2 0 = 1, ' elements 0 and 2 : 2^0 + 2^2 = 5

Dim i Dim iHolder ' if the incorrect parameter is transferred in procedure ' comes back 0 On Error GoTo WhichCheckErr

' binary representation ' a file ÷åêáîêñîâ For i = ctrl. LBound To ctrl. UBound If ctrl (i) = 1 Then ' if will cross out, to add its binary representation iHolder = iHolder Or 2 i End If Next WhichCheckErr: WhichCheck = iHolder

End Function

Function is caused as follows:

iCurChecked = WhichCheck (Check1)

Check1 - a file ÷åêáîêñîâ, iCurChecked - a variable integer. Below the "dual" procedure establishing all ÷åêáîêñû according to a variable in which their binary representations are stored is resulted.

Sub SetChecked (ctrl As Object, _ iCurCheck %) ' This sub sets the binary value of an ' array of controls where iCurChecked is ' 2 raised to the index of each checked ' control Dim i ' in case ctrl is not a valid object On Error GoTo SetCheckErr ' use the binary representation to ' set individual check box controls For i = ctrl. LBound To ctrl. UBound If iCurCheck And (2 i) Then ' if it is checked add in its ' binary value ctrl (i) .Value = 1 Else ctrl (i) .Value = 0 End If Next SetCheckErr:

End Sub

This procedure is caused so:

Call SetChecked (Check1, iDesired)

Check1 - a file ÷åêáîêñîâ, iDesired-a variable storing binary representation of a condition ÷åêáîêñîâ.

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59. CONDITIONAL COMPILATION OF THE CODE

VB4 16/32, VB5 Level: Intermediate

To the majority of developers feature Conditional Compilation from VB4 when you can declare procedures Windows API for 16 or 32-bit OS is known:

#If Win#32 then ' if 32-bit OS Declare SomeApi.... #Else ' if is started 16-digit OS Declare SomeApi #End IF the Same feature can to work not only with functions Windows API, but also with your own functions:

#If Win32 Then Dim lRc& lRc& = ReturnSomeNumber (35000) #Else Dim lRc % lRc % = ReturnSomeNumber (30000) #End If

#If Win32 Then Private Function ReturnSomeNumber_ (lVar&) As Long ReturnSomeNumber = 399999 #Else Private Function ReturnSomeNumber_ (lVar %) As Integer ReturnSomeNumber = 30000 #End If

End Function

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60. TO REDUCE BLINKING DURING LOADING the FORM

VB4, VB5 Level: Intermediate

During loading the form, the following code will help to reduce blinking and flashing GUI by means of functions API:

' Declarations Section #If Win32 Then Declare Function LockWindowUpdate _ Lib "user32" _ (ByVal hwndLock As Long) As Long #Else Declare Function LockWindowUpdate _ Lib "User" _ (ByVal hwndLock As Integer) _ As Integer #End If

Public Sub LoadSomeForm ()

' During loading the form forbids updating a condition of a window ' to get rid of blinking. ' çàïðåùàåòîáíîâëåíèå GUI LockWindowUpdate frmTest.hWnd ' shows the form frmTest. Show ' here a code concerning to loading of the form, etc. ' Never forget to resolve back updating of window LockWindowUpdate 0 End Sub

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61. TO HIDE the INDEX ON CURRENT RECORD in DBGride

VB4 16/32, VB5 Level: Advanced

That the index of record on DBGride did not skip at moving between records (lines grida), use function API LockWindowUpdate (gridname.hwnd) before the beginning of movement on gridó, and LockWindowUpdate (0) after the termination of movings:

Private Sub cmdHideSelector_Click () LockWindowUpdate DBGrid1.hWnd End Sub

Private Sub cmdShowSelector_Click () LockWindowUpdate 0 End Sub

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62. USE POPUP MENUS IN WINDOWS WITHOUT TITLE BAR

VB4 16/32 Level: Intermediate

When you establish property ControlBox in False and BorderStyle in fixed window can receive a window (form) without titlebar (fields of heading). If you will add the menu on this form - the title-bar will appear again. That èçìåæàòü this ïðîáëåììó you can place the menu on other form.

Private Sub Command1_Click () Dim frm As New frmMenu Load frm frm. PopupMenu frm.mnutest ' select specific code Unload frm End Sub

Such behaviour is corrected in VB5

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63. HOW TO LEARN DIVIDERS OF DATE AND TIME WITHOUT FUNCTIONS API

VB3, VB4 16/32, VB5 Level: Intermediate

Here simple algorithm how to learn dividers of date, time and a decimal point in Windows, not getting in Locale Settings or functions API.

DateDelimiter = Mid $ (Format (Date, _ " General Date "), 3, 1) TimeDelimiter = Mid $ (Format (0.5, _ " Long Time "), 3, 1) DecimalDelimiter = Mid $ (Format (1.1, _ " General Number "), 2, 1)

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64. PREVENTION OF MISTAKES AT USE GETSETTING

VB4 16/32, VB5 Level: Intermediate

Use of function GetSetting can generate mistakes, especially in some situations at 16-digit OS at work with INI files. If the required parameter is not present in INI a file you can see the message on a mistake " Invalid procedure call. ". Use mentioned below procedure which substitutes îáðàáîò÷èê mistakes:

Public Function GetRegSetting (AppName _ As Variant, Section As Variant, _ Key As Variant, Optional Default _ As Variant) As Variant

' äåôîëòîâîå value has type, differently it is necessary ' to use word Set Dim tmpValue As Variant

' installation of size by default ' if the size has not been transferred, ' is received an empty variable of type Variant If Not IsMissing (Default) Then _ tmpValue = Default

' it catches possible mistakes On Error Resume Next

' now it is possible to use function from VB tmpValue = GetSetting (AppName, _ Section, Key, tmpValue)

' after possible mistakes the call repeats here ' with already certain value tmpValue GetRegSetting = tmpValue

End Function

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65. DUPLICATION OF LINES OF THE CODE WITHOUT SYNTACTIC MISTAKES

VB3, VB4 16/32, VB5 Level: Beginning Often I should copy a similar code on sense to little changes in each line; for simplification of a problem I do a pattern of that it is necessary to copy, quickly I insert a copy into the necessary place, and I do additions. However often sample text causes mistakes from VB the editor. To overcome this problem it is possible, çàêîììåíòèðîâàâ a pattern before use. When you finish editing the inserted fragment, ðàñêîììåíòèðóéòå it and it is ready. It is especially simple under VB5 in which there is command Block Uncomment. Below the example of addition of a member in a collection is resulted.

While Not mRS.EOF oObject. FName = mRS! FName oObject. LName = mRS! LName oObject. Phone = mRS! Phone.. cCollection. Add oObject, oObject. FName Wend

If at your object of 20 or 30 properties, will create more quickly a pattern:

' oObject. = mRS!

Copy it, insert 20 or 30 times, return to the beginning and âïå÷àòàéòå names of properties and fields, and clean a symbol of the comment. The symbol of the comment allows you to run freely by all fragment, not caring about syntactic mistakes.

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66. The LABEL FOR LOADING LAST EQUIPMENT DESIGN In VB

VB4 32 Level: Intermediate I am frequent ñòàðóòþ VB and I renew work with last project, but I would not like to block up desktop with icons for current works. As the decision I offer my program which needs to be compiled and started on yours desktopå. This program can be applied and to others, using INI files.

Option Explicit

Declare Function GetPrivateProfile_ String Lib "kernel32" _ Alias "GetPrivateProfileStringA" _ (ByVal lpApplicationName As _ String, ByVal lpKeyName As Any, _ ByVal lpDefault As String, _ ByVal lpReturnedString As _ String, ByVal nSize As Long, _ ByVal lpFileName As String) _ As Long

Public Sub Main () Dim temp As String, rVal $, tmp _ As Long rVal $ = String $ (256, 0) tmp = GetPrivateProfileString_ (" Visual Basic ", _ "vb32location", " ", rVal $, _ ByVal Len (rVal $) - 1, _ "c: \windows \vb.ini") temp = Left $ (rVal $, tmp) rVal $ = String $ (256, 0) tmp = GetPrivateProfileString_ (" Visual Basic ", "RecentFile1", _ " ", rVal $, ByVal Len (rVal $) _ - 1, "c: \windows \vb.ini") temp = temp and """ " and Left $ (rVal $, _ tmp) and " """ Shell temp, 1 End End Sub

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67. HOW TO DEDUCE the SYMBOL "and" In LABEL

VB4 16/32, VB5 Level: Beginning

If you want âûûâåñòè a symbol ë&+ on the screen, establish property "UseMnemonic" in False. This property happens it is useful, when, for example, Labelû are used for a conclusion of data from databases. Also you can deduce a symbol "and" in property Caption, having written &&.

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68. CREATION OF TIME FILES

VB3, VB4 16/32, VB5 Level: Beginning

I write a program with the databases, using many auxiliary files at a time. At programming databases it is possible to create time files for a conclusion of result of instruction SQL or from a time database more effectively to work with records. I have written function FileAux, âîçâàðùàþùóþ a name of a time file. If I should create some time files simultaneously, I keep their names in in advance certain variables:

Function FileAux (Ext As String) _ As String Dim i As Long, X As String If InStr (Ext, ".") = 0 Then Ext = "." + Ext End If

' we Search for already available files on the screw i = 0 Do X = "Aux" + Format $ (i, "0000") _ + Ext If FileExists (X) Then i = i + 1 Else Exit Do End If Loop FileAux = X End Function

This function addresses to function FileExists:

Function FileExist (filename As String) _ As Boolean FileExist = Dir $ (filename) <> " " End Function

And here an example of use:

Sub Test () Dim File1 As String, File2 As _ String, File3 As String Dim DB1 As database, DB2 As DataBase Dim FileNum As Integer File1 = FileAux ("MDB") Set DB1 = CreateDataBase (File1) File2 = FileAux ("MDB") Set DB2 = CreateDataBase (File2) File3 = FileAux ("TXT") FileNum = FreeFile Open File3 For OutPut As FileNum ' your code '... Close FileNum End Sub

File1, File2, and File3 should be " Aux0001.MDB, " " Aux0002.MDB, " and " Aux0001.TXT, " accordingly.

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69. MOUSE EVENTS DO NOT HAPPEN IF ENABLE IS ESTABLISHED IN FALSE

VB3, VB4 16/32, VB5 Level: Beginning Events MouseMove do not occur, if property Enabled êîíòðîëà is established in False. My method treats this problem and it can be useful, if you wish to deduce Tooltips or Notes on ñòàòóñáàðå, without dependence from that, enabled êîíòðîë or disabled. If property Enabled êîíòðîëà is established in False êîíòðîë, placed for given, nevertheless áûäåò to respond on movements of the mouse. Copy a code from Command1_MoseMove in Label1_MouseMove. Now you ÌàóñÌóâ works even if Command1 is inaccessible.

Command1 (0), Command1 (1)-Command1 - a file êîíòðîëîâ. Label1 (0), Label1 (1) - a file ëàáåëîâ for êîíòðîëàìè. SSPanel1-Ðàáîòàåò ñòàòóñáàðîì.

Private Sub Form_Load () Dim i As Integer For i = 0 To 1 Label1 (i) .Left = Command1 (i) .Left Label1 (i) .Top = Command1 (i) .Top Label1 (i) .Width = Command1 (i) .Width Label1 (i) .Height = _ Command1 (i) .Height Next i Command1 (0) .enabled = false Command1 (0) .Tag = " Button to Add " Command1 (1) .Tag = " Button to Modify " Command1 (0) .Caption = "&Add" Command1 (1) .Caption = "&Modify"

End Sub

Private Sub Label1_MouseMove (Index As _ Integer, Button As Integer, Shift _ As Integer, X As Single, Y As _ Single) SSPanel1. Caption = Command1 (Index) .Tag End Sub

Private Sub Command1_MouseMove (Index _ As Integer, Button As Integer, _ Shift As Integer, X As Single, Y _ As Single) SSPanel1. Caption = Command! (Index) .tag End Sub

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70. HOW TO DEDUCE THE POPUP MENU ON TEXT BOXES

VB4 16/32, VB5 Level: Intermediate

The some people êîíòðîëû in VB4 and VB5 as, for example, TextBox have the contextual menu which is creeping out at right clique on the specified control on a default. If you want, that another left êîòåêñòíîå the menu standard methods or ïðîïåðòåé for this purpose do not exist. The output consists in îòëàâëèâàíèè events Mouse_Down which code will do êîíòðîë inaccessible. Then âûñâå÷èâàéòå your contextual menu, ýíàáëèòå êîíòðîë back. Procedure PopContextMenu describes the specified method

Sub PopContextMenu (argoControl As _ Control, argoMenu As Control) argoControl. Enabled = False PopupMenu argoMenu argoControl. Enabled = True End Sub

Example of a call in event MouseDown for òåêñòáòîêñà by name Text1 and menu MyMenu:

Private Sub Text1_MouseDown (Button As _ Integer, Shift As Integer, X As _ Single, Y As Single) If Button = vbRightButton Then PopContextMenu Text1, MyMenu End If End Sub

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71. TO ALIGN the FORM In view of ÒÀÑÊÁÀÐÀ

VB3, VB4 16/32, VB5 Level: Intermediate For a centering of the form you should cause only API procedure, and to get two constants. This decision is based on that fact, that GetSystemMetrics returns true value of parameters of the screen which can be borrowed actually òàñêáàðîì and Microsoft Office shortcut barîì:

Public Const SM_CXFULLSCREEN = 16 Public Const SM_CYFULLSCREEN = 17

#If Win32 then Declare Function GetSystemMetrics _ Lib "user32" _ (ByVal nIndex As Long) As Long #Else Declare Function GetSystemMetrics _ Lib "User" _ (ByVal nIndex As Integer) _ As Integer #End If

Public Sub CenterForm (frm As Form) frm. Left = Screen. TwipsPerPixelX * _ GetSystemMetrics_ (SM_CXFULLSCREEN) / 2 _ - frm. Width / 2 frm. Top = Screen. TwipsPerPixelY * _ GetSystemMetrics_ (SM_CYFULLSCREEN) / 2 _ - frm. Height / 2 End Sub

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72. CLEARING THE LINE OF UNNECESSARY SYMBOLS

VB3, VB4 16/32, VB5 Level: Beginning Sometimes happens it is useful to have function which clears a line of undesirable symbols. This small function accepts as parameters a line for clearing and a symbol of which it should be cleared:

Function StringCleaner (s As String, _ Search As String) As String Dim i As Integer, res As String res = s Do While InStr (res, Search) i = InStr (res, Search) res = Left (res, i - 1) and _ Mid (res, i + 1) Loop StringCleaner = res End Function

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73. CHECK of OBJECTS BY MEANS OF TYPENAME

VB4 16/32, VB5 Level: Beginning

You can define a class to which the object belongs, by means of function TypeName instead of use of block If TypeOf. Use expression TypeOf for definition of type of object:

If TypeOf myObject is myType then... We do that End If

You can make the same ñàâìîå by means of a following code:

if TypeName (myObject) = "myType" Then.... We do that.... End If

Benefit of my decision that to you is not so obligatory to include in your project all classes (or OCXs) with which you work. It is quite good reception for a writing of the general procedures (universal, a general purpose) and, moreover, you can use TypeName in complex checks and blocks Select Case.

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74. ADDITION OF THE LINE IN TEXT BOX

VB4 16/32, VB5 Level: Intermediate

Use the given code to force ñêðîëëåð TextBoxà to move automatically when you add the new text:

' Transition by the end of text MyTextBox. SelStart = Len (MyTextBox. Text) ' the new text will stand here MyTextBox. SelText = NewText $

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75. CHECK OF ARGUMENTS IN FUNCTION VAL

VB3, VB4 16/32, VB5 Level: Beginning

At use of function Val, VB is capricious, generating a mistake of discrepancy of types. For example, Val (" 25 % ") correctly returns 25 whereas Val (" 2.5 % ") the entrance parameter incorrectly interprets and returns a mistake of discrepancy of types. It happens only when at a line there is a decimal point and a symbol of "%" or "and". To correct it, clean these symbols from a line before its transfer in Val.

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76. LABELS FOR INTERNET

VB4 32, VB5 Level: Advanced

VB5 App Wizard is able to create Web the Browser-form, but it works only with Microsoft Internet Explorer and you should drag behind yourselves SHDOCVW.DLL at distribution of a program. If you use function ShellExecute for start of file Internet Shortcut Windows starts äåôîëòíûé a browser and passes on specified URL. This method works as Microsoft and with Netscape browsers if they are correctly registered in the register, and you do not need to move any DLL at distribution of a program.

Private Declare Function ShellExecute _ Lib "shell32.dll" Alias _ "ShellExecuteA" _ (ByVal hwnd As Long, _ ByVal lpOperation As String, _ ByVal lpFile As String, _ ByVal lpParameters As String, _ ByVal lpDirectory As String, _ ByVal nShowCmd As Long) As Long Private Const SW_SHOWNORMAL = 1

' frm: ShellExecute uses îáðàáîò÷èê windows. ' you can use îáðàáîò÷èê the main window of a program ' sUrl: this name and a way to a file .url (file Internet shortcut) ' specifying your page, íàïð. ' c: \MyWebPage.url uses Internet Explorer ' for creation of a file of a label

Public Sub GoToMyWebPage (frm as Form, _ sUrl as string) Dim lRet as Long lRet = ShellExecute (frm.hwnd, _ "open", sUrl, vbNull, _ vbNullString, SW_SHOWNORMAL) If lRet <= 32 Then ' there was a mistake. Some of mistakes, ' returned ShellExecute: ' ERROR_FILE_NOT_FOUND = 2& ' ERROR_PATH_NOT_FOUND = 3& ' ERROR_BAD_FORMAT = 11& ' SE_ERR_NOASSOC = 31 ' SE_ERR_OOM = 8 Else ' if the browser is started! End If End Sub

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77. VIEWING MAINTENANCE HELP-ÔÀÉËÀ

VB4 32, VB5 Level: Intermediate

Many programmers like to add to the to appendices and the help-files. How to open the maintenance help-file Windows from your program? Here an example of a code with use Win32 API of function.

' - ---Announcement Const HELP_CONTENTS = &H3& ' Functions of the Conclusion of contents Declare Function WinHelp Lib "user32" _ Alias "WinHelpA" _ (ByVal hwnd As Long, _ ByVal lpHelpFile As String, _ ByVal wCommand As Long, _ ByVal dwData As Long) As Long

' ---Code Sub OpenHelpFile (HelpFileName As String) ' HelpFileName - a way to the help-file. WinHelp hwnd, HelpFileName, _ HELP_CONTENTS, 0 End Sub

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78. THE TASK OF BORDERS MDI OF THE FORM PRECISELY AS IN DESIGN-TIME

VB3, VB4 16/32, VB5 Level: Beginning

As MDI-forms have properties border, the user can move apart their borders and change the size of MDI-forms. If the user tries to change the sizes of the form, and I do not want it (let remains such as have been created by me) procedure for event MDIForm_Resize () will rescue (whom - to taste):

Private Sub MDIForm_Resize () ' the Interdiction resizingà MDI-forms (extension of borders and its moving ìûøîé). ‘ Ãîäèòñÿòîëüêî for those MDI forms which are deduced as Normal Window If WindowState = 0 Then ' the set height MDI of form Me. Height = 6900 ' the set width MDI of form Me. Width = 10128 ' set left edge MDI of form Me. Left = 1020 ' set right edge MDI of form Me. Top = 1176 ' with the same success it is possible to use method Move to unite ‘ restoration of coordinates of the form in one command End If End Sub

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79. FAST SEARCH In the DATABASE

VB3, VB4 16/32, VB5 Level: Beginning In VB there is no built in procedure of type DLookUp from Àêñåññà. You can use a mentioned below code for reception Name of object on it ID:

Public Function MyDLookUp (Column As _ String, TableName As String, _ Condition As String) As Variant Dim Rec As Recordset On Error GoTo MyDlookUp_Err

' gCurBase - global ïåðåìåíàÿ, specifying on òåêóùêþ DB Set Rec = gCurBase. OpenRecordset_ (" Select * From " and TableName) Rec. FindFirst Condition If Not Rec. NoMatch Then ' returns a required field if it is found MyDLookUp = Rec (Column) Exit Function End If

' return if it is not found, or there was other mistake MyDlookUp_Err: MyDLookUp =-1 End Function

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80. EASY TRACKING POSITION OF FOCUS

VB3, VB4 16/32, VB5 Level: Intermediate

Lost_Focus and Got_Focus events are often used for check of correctness of input of the text. You can use a mentioned below code for tracking focus on the form I do not program everyone êîíòðîë separately. Ïðìåñòèòå timer control on the form, establish Interval property = 100 and Enabled = True. Name the control tmrFocusTracking. Timer event should ñîäåðäàòü a following code:

Private Sub tmrFocusTracking_Timer () Dim strControlName As String Dim strActive As String strControlName = _ Me. ActiveControl. Name

Do strActive = Me. ActiveControl. Name If strControlName <> strActive _ Then Print strControlName and _ " - Lost Focus ", _ strActive and " - Got Focus " strControlName = strActive End If DoEvents Loop End Sub

To implement universal highlighting, replace the Print statement with this code:

Me. Controls (strActive) .SelStart = 0 Me. Controls (strActive) .SelLength = _ Len (Me. Controls (strActive))

For check (validation) correctness of the text instead of Print statement use a call of procedure of check. Use strActive in a Select Case structure By the moment when there is command Print, strActive it is equal êîíòðîëó, having focus, and strControlName contains a name êîíòðîëà which has lost focus. Do not place this procedure somewhere except for the timer.

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81. NOT CLOSED FORM

VB3, VB4 16/32, VB5 Level: Beginning

If to expose property ControlBox on the form in False buttons Minimize and Maximize too will disappear. We shall assume, that you wish to enable nevertheless to the user to use buttons Minimize and Maximize, but thus that it could not close the form the button with a dagger. Add a following code in event Query_Unload:

' if at you VB3, ðàñêîììåíòèðóéòå a next line ' Const vbFormControlMenu = 0 Private Sub Form_QueryUnload (Cancel As _ Integer, UnloadMode As Integer) If UnloadMode = vbFormControl_ Menu Then Cancel = True End If End Sub

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82. TO CHANGE PROPERTY TO THE WHOLE GROUP KONTROLOV

VB3, VB4 16/32, VB5 Level: Beginning

You can easily make visible/invisible the whole group êîíòðîëîâ. In a mode of development, allocate all êîíòðîëû with which you will make the given operation at performance of the program. Press F4, and appropriate to property Tag a name of group, for example Group1. Now at fulfilment of group operation you will be helped by a following code:

For ind = 0 To Formname. Controls. Count _ - 1 If Formname. Controls (ind) .Tag = _ "Group1" Then Formname. Controls (ind) .Visible _ = True End If Next

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83. HOW SIMPLY TO FORMAT AND APPROXIMATE NUMBER

VB3, VB4 16/32, VB5 Level: Intermediate

Example of a rounding off with the set accuracy.

n = 12.345 Format (n, "0.00\0") ' returns " 12.350" Format (n, "0.\0\0") ' returns " 12.00" Format (0.55, " #.0 \0 ") ' returns " .60"

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84. BE CAUTIOUS, HERE TO YOU NOT WITH!

VB3, VB4 16/32, VB5 Level: Intermediate

VB the programmers who have got used to With, can be confused following feature VB. We shall consider a code:

Dim x As Integer Dim y As Integer Dim z As Integer x = 10 y = 20 z = 0 ' let function max returns greater of two numbers if (z = max (x, y))> 0 then Msgbox CStr (z) Else Msgbox " How Come? " End if

You expect, what will be highlighted 20 how should occur in With? However, VB will compare z with RHS (right-hand side) the-right party, even before assignment, irrespective of brackets. Be close.

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8.5 TO USE BACKQUOTES INSTEAD OF APOSTROPHES

VB3, VB4 16/32, VB5 Level: Intermediate Often at use Transact-SQL I should intercept comments of the user from òåêñòáîêñà and to send them to a database. However, if the user presses an apostrophe in òåêñòáîêñå, there is a mistake of time of performance as SQL Server uses an apostrophe as an attribute of the end of a line. To bypass this problem, intercept input of the user in event KeyPress and replace an apostrophe on here such êàâû÷êó «‘» (ASCII (145)):

Private Sub Text1_Keypress_ (KeyAscii as Integer) If KeyAscii = 39 Then KeyAscii = 145 End If End Sub

Also it is possible to replace all unary inverted commas on «‘» before sending in SQL Server.

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86. DISTRIBUTION OF NEW VERSIONS OF THE PROGRAM ON THE NETWORK

VB4 16/32, VB5 Level: Intermediate

I write VB programs for a network with approximately 300 users. Difficultly enough in due time to follow distribution of each new version of a program by all machines, therefore I use such feature VB àâòîèíêðåìåíòèðóþùàÿñÿ numbering of versions for check, whether the upgrade of a program by the concrete machine is required. At compilation of a program establish àâòîèíêðåìåíò versions in On. Keep yours setup/upgrade files on a network disk (urgently I recommend to use UNC-ways (\\ ¿¼n_¼áÞ¿¡Ù \¿¼n_ñ¿ß¬á) rather than simply names of disks), and put an INI-file of a program in which number of the newest version is specified. Then insert a following code into a program, event Form_Load:

Open IniFile $ For Input As #1 Line Input #1, sUpgradeVersion $ Close #1

If sUpgradeVersion> (Format (App. Major, "00") and "." And _ Format (App. Minor, "00") and "." And _ Format (App. Revision, "0000")) Then ' start of a upgrade from network disk End End If

If the version in an INI-file above, than the version which has been written down in .exe the program the automatic device will start the program of a upgrade on a network and will finish the performance, that is all the necessary files can be replaced. It is especially useful, when you only start to write a program, that is upgrades and ôèêñû appear almost time in some days.

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87. TO CLOSE THE WINDOW OF THE PROGRAM AS IT DOES WINDOWS 95

VB3, VB4 16/32, VB5 Level: Intermediate

Place this code in declaration section the module:

Public Sub Win95Shrivel (xForm As Form) ' minimizes a window xForm. WindowState = 1 End Sub

Cause it from procedure Unload of the form

Private Sub Form_Unload (Cancel As _ Integer) Win95Shrivel Me End Sub

Each time at unloade forms it all over again áûðåíüêî is turned off to òàñêáàðó, and then disappears. It works and in Windows 3.1x too.