C#全局钩子是否支持异步操作-乐工具技术知识

C# 全局钩子本身不直接支持异步操作。全局钩子通常用于监听键盘、鼠标等输入事件，这些事件需要实时处理，因此通常使用同步方法。然而，你可以在全局钩子的回调函数中使用异步操作。

以下是一个使用 C# 全局钩子并在回调函数中使用异步操作的示例：

using System;
using System.Threading.Tasks;
using System.Windows.Forms;

public class GlobalHookExample
{
    private static LowLevelKeyboardProc _keyboardProc;
    private static IntPtr _hookID = IntPtr.Zero;

    public static void Main()
    {
        _keyboardProc = KeyboardHookCallback;
        _hookID = SetHook(_keyboardProc);

        Application.Run();

        UnhookWindowsHookEx(_hookID);
    }

    private static IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (var curProcess = System.Diagnostics.Process.GetCurrentProcess())
        using (var 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 KeyboardHookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        {
            int vkCode = Marshal.ReadInt32(lParam);
            Task.Run(() => HandleKeyDownAsync((Keys)vkCode));
        }

        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

    private static async Task HandleKeyDownAsync(Keys key)
    {
        // 在这里处理按键事件，例如：
        await Task.Delay(1000);
        Console.WriteLine($"Key pressed: {key}");
    }

    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;

    [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);
}

在这个示例中，我们创建了一个全局键盘钩子，当按键事件发生时，KeyboardHookCallback 函数会被调用。在这个函数中，我们使用 Task.Run 将 HandleKeyDownAsync 函数作为异步任务运行。这样，HandleKeyDownAsync 函数中的代码将在后台线程上执行，而不会阻塞主线程。