C＃检查是否有多个键被按下（全局键盘挂钩）

Question

我正在制作一个C＃表单应用程序在后台运行，并检查您是否按下CTRL + A + S.所以我正在检查互联网上的论坛和我已经设置该应用程序在后台运行，现在我试图设置键盘钩子。我在互联网上找到了一个全局键盘钩子代码。

下面是该代码：

// GLOBAL HOOK 
    [DllImport("user32.dll")] 
    static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc callback, IntPtr hInstance, uint 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")] 
    static extern IntPtr LoadLibrary(string lpFileName); 

    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam); 

    const int WH_KEYBOARD_LL = 13; // Number of global LowLevel- hook on the keyboard 
    const int WM_KEYDOWN = 0x100; // Messages pressing 

    private LowLevelKeyboardProc _proc = hookProc; 

    private static IntPtr hhook = IntPtr.Zero; 

    public void SetHook() 
    { 
     IntPtr hInstance = LoadLibrary("User32"); 
     hhook = SetWindowsHookEx(WH_KEYBOARD_LL, _proc, hInstance, 0); 
    } 

    public static void UnHook() 
    { 
     UnhookWindowsHookEx(hhook); 
    } 

    public static IntPtr hookProc(int code, IntPtr wParam, IntPtr lParam) 
    { 
     if (code >= 0 && wParam == (IntPtr)WM_KEYDOWN) 
     { 
      int vkCode = Marshal.ReadInt32(lParam); 

      if (vkCode.ToString() == "162") //162 is ASCI CTRL 
      { 
       MessageBox.Show("You pressed a CTRL");      
      } 
      return (IntPtr)1; 
     } 
     else 
      return CallNextHookEx(hhook, code, (int)wParam, lParam); 
    } 

    private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e) 
    { 
     // Remove the hook 
     UnHook(); 
    } 

    private void Form1_Load(object sender, EventArgs e) 
    { 
     // Set the hook 
     SetHook(); 
    } 

} 

我的问题是，这个钩子是设置为1个键，我无法弄清楚如何检查是否被按下3个键（Ctrl + A + S） 。

我已经试过这个，但没有工作。

if (vkCode.ToString() == "162" && vkCode.ToString() == "65" && vkCode.ToString() == "83") //162 is CTRL, 65 is A, 83 is S, ASCII CODE 
      { 
       MessageBox.Show("You pressed a CTRL + A + S");      
      } 

所以我的问题是什么，我需要做的是，程序或该钩子将让我检查3个按键（CTRL + A + S）。

Answer 1

我相信你不得不分别检测CTRL，A和S，使用标志来保持CTRL和A是否是最后的按键，像这样的轨道：

static bool ctrlPressed = false; 
static bool ctrlAPressed = false; 

public static IntPtr hookProc(int code, IntPtr wParam, IntPtr lParam) 
{ 
    if (code >= 0 && wParam == (IntPtr)WM_KEYDOWN) 
    { 
     int vkCode = Marshal.ReadInt32(lParam); 

     if (vkCode == 162 || vkCode == 163) //162 is Left Ctrl, 163 is Right Ctrl 
     { 
      ctrlPressed = true; 
     } 
     else if (vkCode == 65 && ctrlPressed == true) // "A" 
     { 
      ctrlPressed = false; 
      ctrlAPressed = true; 
     } 
     else if (vkCode == 83 && ctrlAPressed == true) // "S" 
     { 
      ctrlPressed = false; 
      ctrlAPressed = false; 
      MessageBox.Show("Bingo!"); 
     } 
     else 
     { 
      ctrlPressed = false; 
      ctrlAPressed = false; 
     } 

     // return (IntPtr)1; // note: this will interfere with keyboard processing for other apps 
    } 
// else // don't interfere , always return callnexthookex 
     return CallNextHookEx(hhook, code, (int)wParam, lParam); 
} 

如果你想牛逼omake确保所有按下的逻辑是相似的，你只需要添加检查按键是否按下或向上。你也可以想出一个更聪明的方法来做到这一点，这使用某种列表或队列或按键的东西。