56. FAQ o Win API

Q> How to process messages from a wheel ms intellimouse? 
A> 

For BCB: (does not work in Win95) 

In a file unit1.h: 

#ifndef WM_MOUSEWHEEL 
#define WM_MOUSEWHEEL 0x020A 
#endif 
.
.
.

 public://User declarations 

     __ fastcall TForm1 (TComponent * Owner); 

void __ fastcall OnWheel (TMessage &msg); 

BEGIN_MESSAGE_MAP 
MESSAGE_HANDLER (WM_MOUSEWHEEL, TMessage, OnWheel) 
END_MESSAGE_MAP (TForm) 

In a file unit1.cpp: 

void __ fastcall TForm1:: OnWheel (TMessage &msg) 
{ 

if (HIWORD (msg. WParam) <=32512) 
{<moved up>}; 
else 
{<moved down>}; 

}

For MSVC: 

The IntelliMouse (the mouse with the wheel in the center) is pretty neat. 
You can register to get the wheel messages from it in your top level frame.  
If you want to handle the message in a view you must pass the message down  
manually as is illustrated. To get messages from the wheel add the following  
to your application: 

To make the wheel act like a simple middle button just add handlers for: 

WM_MBUTTONDOWN 
WM_MBUTTONUP 

and so-on just like left and right buttons.  
You will not find this in the class wizzard but you can add them manually. 
  
For wheel messages do the following: 

Declare a global in your app as follows: 

UINT uMSH_MOUSEWHEEL; 

and everyplace else declare an external so you can get at it 
extern UINT uMSH_MOUSEWHEEL; 
  
In your initialization code register the following message 
uMSH_MOUSEWHEEL = RegisterWindowMessage ("MSWHEEL_ROLLMSG"); 
  
(In the MAIN FRAME add the following: 

To the message map in the.H file add 
afx_msg LONG OnWheel (UINT a, LONG b); 

To the message map in the.CPP file add 
ON_REGISTERED_MESSAGE (uMSH_MOUSEWHEEL, OnWheel)  

And then add the message handler as follows 

LONG CMainFrame:: OnMouseWheel (UINT nFlags, LONG pValue)  
{ 
	if (nFlags AND 0x0100)//Rolled in 
	{ 
		//do rolled in stuff here 
	}
	else//Rolled out 
	{ 
		//do rolled out stuff here 
	}
	return 0; 
}

  
if you want to receive this message in a view then add the same handlers 
shown above to your view and then do the following in your main frame. 

LONG CMainFrame:: OnWheel (UINT a, LONG b) 
{ 
	BOOL yn; 
	MDIChildWnd* aw = (MDIChildWnd *) MDIGetActive (&yn);  
	if (aw) 
	{ 
		CView * junk; 
		junk = aw-> GetActiveView (); 
		if (junk) 
			junk-> SendMessage (uMSH_MOUSEWHEEL, a, b); 
	}
	return 0; 
}

In more details about all it it is possible to esteem in MS Intellimouse SDK