在c＃.net 3.5中凍結全局低級別鍵盤鉤

Question

我註冊全局鉤子時遇到了令人沮喪的問題。 我使用這個類在我的Windows應用程序：

using System; 
using System.Diagnostics; 
using System.Runtime.InteropServices; 
using System.Windows.Forms; 

class InterceptKeys 
{ 
    private const int WH_KEYBOARD_LL = 13; 
    private const int WM_KEYDOWN = 0x0100; 
    private static LowLevelKeyboardProc _proc = HookCallback; 
    private static IntPtr _hookID = IntPtr.Zero; 

    public static void Hook() 
    { 
     _hookID = SetHook(_proc); 
    } 

    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) 
     { 
      MessageBox.Show("Test"); 
     } 
     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); 
} 

這裏是Program.cs的

namespace TestHooks 
{ 
    static class Program 
    { 
     /// <summary> 
     /// The main entry point for the application. 
     /// </summary> 
     [STAThread] 
     static void Main() 
     { 
      InterceptKeys.Hook(); 
      Application.EnableVisualStyles(); 
      Application.SetCompatibleTextRenderingDefault(false); 
      Application.Run(new Form1()); 
     } 

    } 
} 

一切工作（消息框彈出），但窗口凍結了一會兒，蜂鳴器鳴叫。在Vista上，Windows 7上不會出現這個問題。有什麼建議嗎？

Answer 1

您不能在代碼中使用MessageBox。它阻止執行，鍵盤死亡。例如，使用Console.WriteLine（），輸出將轉到Visual Studio輸出窗口。

請注意，此代碼不再適用於.NET 4.0，GetModuleHandle（）將返回NULL。