我寫的實用程序需要使用SetWindowsHookEx
函數來捕獲LowLevelKeyboardProc
回調的按鍵。鍵捕獲:WM_KEYDOWN最後一個鍵狀態位總是== 0
我已經實施在this MSDN blog上找到的代碼。
正確的鍵碼被捕獲,但我似乎無法使用從答案帶到這個StackOverflow的問題掩碼時,爲了獲得第30位的正確值:Get 30th bit of the lParam param in WM_KEYDOWN message
private const int LAST_KEY_STATE_BITMASK = 0x40000000;
此位應根據Microsoft documentation,允許我檢測鑰匙是否被扣下。
我只想在第一次按下按鍵時未按住keydown事件; keyup是不夠的。
我使用的嘗試,並獲得第30位的值的代碼是:
int vkCode = Marshal.ReadInt32(lParam);
int lastKeyState = (vkCode & LAST_KEY_STATE_BITMASK);
其中,從我的理解,應該返回0時鍵沒有被按住1時是。
我也嘗試使用lParam.ToInt32()
和(int)lParam
代替vkCode
,但無濟於事。
請幫忙!
下面是完整的程序,因爲它是在其目前的狀態:
using System;
using System.Diagnostics;
using System.Windows.Forms;
using System.Runtime.InteropServices;
public class KeyCapture
{
private const int WH_KEYBOARD_LL = 13;
private const int WM_KEYDOWN = 0x0100;
private const int LAST_KEY_STATE_BITMASK = 0x40000000;
private static LowLevelKeyboardProc _proc = HookCallback;
private static IntPtr _hookID = IntPtr.Zero;
public static void Main()
{
_hookID = SetHook(_proc);
Application.Run();
UnhookWindowsHookEx(_hookID);
}
private static IntPtr SetHook(LowLevelKeyboardProc proc)
{
using (Process curProcess = Process.GetCurrentProcess())
using (ProcessModule curModule = curProcess.MainModule)
{
return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
GetModuleHandle(curModule.ModuleName), 0);
}
}
private delegate IntPtr LowLevelKeyboardProc(
int nCode, IntPtr wParam, IntPtr lParam);
private static IntPtr HookCallback(
int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
{
int vkCode = Marshal.ReadInt32(lParam);
int lastKeyState = (vkCode & LAST_KEY_STATE_BITMASK);
Console.WriteLine((Keys)vkCode + "|" + vkCode + "|" + lastKeyState);
}
return CallNextHookEx(_hookID, nCode, wParam, lParam);
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook,
LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UnhookWindowsHookEx(IntPtr hhk);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
IntPtr wParam, IntPtr lParam);
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string lpModuleName);
}
[閱讀文檔](http://msdn.microsoft.com/en-us/library/windows/desktop/ms644985.aspx)。您似乎認爲傳遞給'LowLevelKeyboardProc'的lParam'遵循與傳遞給'WM_KEYDOWN'消息的'lParam'相同的約定。情況並非如此:在'LowLevelKeyboardProc'中,'lParam'是「一個指向'KBDLLHOOKSTRUCT'結構的指針。」 –
@IgorTandetnik現在我覺得很傻!在用有意義的變量名稱注視C#一天之後,我必須撇清這一點。非常感謝您的快速回復。 – cpoliver
@IgorTandetnik請原諒我的無知(自從您的回覆以來,我一直在無情地尋找),但是您能否瞭解我如何閱讀WM_KEYUP消息的lParam以獲取我感興趣的位? – cpoliver