Subject: RE: System-wide Keyhandler
From: "Lion Shi"
Sent: 5/23/2002 6:29:51 AM
Hello Jim,
You can use system hook to hook keyboard messages and then determine if the
key are pressed. This is a sample code demonstrating how to setup a system
hook in C#:
public class Win32Hook
{
[DllImport("kernel32")]
public static extern int GetCurrentThreadId();
[DllImport( "user32",
CharSet=CharSet.Auto,CallingConvention=CallingConvention.StdCall)]
public static extern int SetWindowsHookEx(
HookType idHook,
HOOKPROC lpfn,
int hmod,
int dwThreadId);
public enum HookType
{
WH_KEYBOARD = 2
}
public delegate int HOOKPROC(int nCode, int wParam, int lParam);
public void SetHook()
{
// set the keyboard hook
SetWindowsHookEx(HookType.WH_KEYBOARD,
new HOOKPROC(this.MyKeyboardProc),
0,
GetCurrentThreadId());
}
public int MyKeyboardProc(int nCode, int wParam, int lParam)
{
//Perform your process
return 0;
}
}
And then you can install the hook procedure by the following code:
Win32Hook hook = new Win32Hook();
hook.SetHook();
In the MyKeyboardProc function, you can determine which key is pressed by
the wParam parameter. You also can identify the key is pressed or released
by the lParam parameter. Then you can set a flag when the Ctrl is pressed
and set another flag when the Alt is pressed. When both flag are set, stop
the program.
For more information about these two parameters, please see:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/hooks _8k6b.asp
You can find all Virtual-Key Code Definitions from the link below:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmeother/ke
ycnt_4fqw.asp
I hope it is helpful.
Best regards,
Lion Shi, MCSE, MCSD
Microsoft Support Engineer
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use. 2001 Microsoft Corporation. All rights
reserved.
--------------------
From: "Jim Baker" <jim.baker@>
Subject: System-wide Keyhandler
Date: Mon, 20 May 2002 13:05:30 -0400
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I'm looking to have a program grab a key combination (whether it has focus
or not) and run an event based on that. It's basically a system tray
application that I want to toggle hiding and showing a window. Any ideas?
Jim
