user32.dll
을 사용한 Keyboard Hook 샘플입니다.
[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, KeyboardProc callback, IntPtr hInstance, int threadId);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("user32.dll")]
static extern IntPtr CallNextHookEx(IntPtr idHook, int nCode, int wParam, IntPtr lParam);
[DllImport("kernel32.dll", CallingConvention = CallingConvention.StdCall)]
private static extern int GetCurrentThreadId();
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
실행 중인 어플리케이션에서만 Keyboard Hook을 하기 위해 SetWindowsHookEx
메서드의 첫번째 파라미터인 idHook에 WH_KEYBOARD
을 넘겨주었다.
Windows 전역에서 Keyboard Hook을 하기 위해서는 idHook에 WH_KEYBOARD_LL
을 파라미터로 줘야한다. WH_KEYBOARD
와 WH_KEYBOARD_LL
는 각각 hook procedure가 다르므로 주의해야 한다.
WH_KEYBOARD |
WH_KEYBOARD_LL |
|
---|---|---|
Value | 2 | 13 |
Scope | Thread or global | Global only |
Hook Procedure | KeyboardProc | LowLevelKeyboardProc |
private const int WH_KEYBOARD = 2;
public void SetHook()
{
IntPtr hInstance = LoadLibrary("User32");
hHook = SetWindowsHookEx(WH_KEYBOARD, _proc, hInstance, GetCurrentThreadId());
}
lParam
의 KF_REPEAT
플래그를 통해 반복 호출을 피한다.
private const int HC_ACTION = 0;
private const int KF_REPEAT = 0x4000;
private IntPtr HookProc(int code, IntPtr wParam, IntPtr lParam)
{
if (code == HC_ACTION)
{
var repeat = HiWord(lParam) & KF_REPEAT;
if (repeat == 0)
{
Debug.WriteLine($"{code} / {wParam} / {lParam}");
switch ((int)wParam)
{
case VK_F1:
this.txb.Text += "F1 was pressed" + Environment.NewLine; break;
case VK_F2:
this.txb.Text += "F2 was pressed" + Environment.NewLine; break;
case VK_F3:
this.txb.Text += "F3 was pressed" + Environment.NewLine; break;
case VK_F4:
this.txb.Text += "F4 was pressed" + Environment.NewLine; break;
case VK_F5:
this.txb.Text += "F5 was pressed" + Environment.NewLine; break;
case VK_F6:
this.txb.Text += "F6 was pressed" + Environment.NewLine; break;
}
}
}
return CallNextHookEx(hHook, code, (int)wParam, lParam);
}
private static ulong HiWord(IntPtr ptr)
{
if (((ulong)ptr & 0x80000000) == 0x80000000)
return ((ulong)ptr >> 16);
else
return ((ulong)ptr >> 16) & 0xffff;
}
F1부터 F6를 차례로 눌렀을 때 텍스트박스에 미리 설정해 둔 텍스트가 입력된다.