How to use WinAPI in C#??? 1

[minhhoa]

Does anyone know how to declare the funtions: SetWindowLong and CallWindowProc (in User32.dll) and how to use them in C#?

Thanks.

 

[chiph]

Look in the docs for dllImport.

Chip H.

 

[minhhoa]

Thanks for your help. I get problems on the type convertion. Could you give me more details?

 

[chiph]

Can you post your code?

Chip H.

 

[minhhoa]

Here it is:

//*******************************************************//

using System;

namespace CSToolWinAddin
{
/// <summary>
/// Summary description for HookMessage.
/// </summary>
///
using System.Runtime.InteropServices;

delegate void MsgEventHandler(object source, MsgEventArgs e);

public class MsgEventArgs: EventArgs
{
public int hWnd;
public int uMsg;
public int wParam;
public int lParam;

public MsgEventArgs(int hWnd, int uMsg, int wParam, int lParam)
{
this.hWnd = hWnd;
this.uMsg = uMsg;
this.wParam = wParam;
this.lParam = lParam;
}
}

class HookMessage
{
const int GWL_WNDPROC= -4;
private int pPrevProc, hWnd;

delegate int MyCallBack(int hWnd, int message, int wParam, int lParam);

[DllImport(&quot;User32.dll&quot]
public static extern int SetWindowLong(int hWnd, int nIndex, int newLong);

[DllImport(&quot;User32.dll&quot;, CharSet=CharSet.Auto)]
public static extern int CallWindowProc (int pPrevProc, int hWnd, int message,int wParam,int lParam);

public event MsgEventHandler OnMessage;

public HookMessage(int wHandle)
{
hWnd = wHandle;
MyCallBack wndProc= new MyCallBack(WindowProc);
pPrevProc = SetWindowLong(hWnd, GWL_WNDPROC, (int)wndProc);
}

~HookMessage()
{
SetWindowLong(hWnd, GWL_WNDPROC, pPrevProc);
}

public int WindowProc(int hWnd, int message, int wParam, int lParam)
{
//WindowProc = CallWindowProc(pPrevProc, hWnd, message, wParam, lParam);
MsgEventArgs args= new MsgEventArgs(hWnd,message,wParam,lParam);
this.OnMessage(this,args);
return CallWindowProc(pPrevProc, hWnd, message, wParam, lParam);
}
}
}

//*******************************************************//

The compile error is &quot;D:\Temp\HookMessage.cs(50): Cannot convert type 'CSToolWinAddin.HookMessage.MyCallBack' to 'int'&quot;.

Thanks anyway.

 

[chiph]

OK, maybe I need to understand why you're trying to do this. If you're trying to hook another processes window messages, that requires a system-wide hook, which isn't really recommended.

You might want to take a look at:

http://www.codeproject.com/cs/menu/vsnettoolbar.asp

Chip H.

 

[minhhoa]

It doesn't meet my requirement. Thanks anyway.

I'm trying to hook another processes window messages but I don't know why it isn't recommended !!!