C#全局鉤子是否支持異步操作

c#
小樊
82
2024-09-11 02:32:44

C# 全局鉤子本身不直接支持異步操作。全局鉤子通常用于監(jiān)聽(tīng)鍵盤(pán)、鼠標(biāo)等輸入事件，這些事件需要實(shí)時(shí)處理，因此通常使用同步方法。然而，你可以在全局鉤子的回調(diào)函數(shù)中使用異步操作。

以下是一個(gè)使用 C# 全局鉤子并在回調(diào)函數(shù)中使用異步操作的示例：

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)
    {
        // 在這里處理按鍵事件，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);
}

在這個(gè)示例中，我們創(chuàng)建了一個(gè)全局鍵盤(pán)鉤子，當(dāng)按鍵事件發(fā)生時(shí)，KeyboardHookCallback 函數(shù)會(huì)被調(diào)用。在這個(gè)函數(shù)中，我們使用 Task.Run 將 HandleKeyDownAsync 函數(shù)作為異步任務(wù)運(yùn)行。這樣，HandleKeyDownAsync 函數(shù)中的代碼將在后臺(tái)線(xiàn)程上執(zhí)行，而不會(huì)阻塞主線(xiàn)程。

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