最小化的程序如何监听,但仍然允许键盘事件?

时间:2016-03-14 14:18:22

标签: c# winforms keyboard-events keyboard-hook winforms-interop

目标是使应用程序最小化,以响应键盘按下 键盘按下仍然可以影响其他焦点应用程序。

我发现在最小化应用程序中检测键盘按下的唯一方法,
是使用低级键盘钩:

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

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 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);
            Console.WriteLine((Keys)vkCode);
        }
        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);
}

这样可以,但它可以防止按键对其他焦点窗口产生任何影响。我希望最小化的应用程序能够听这些键盘按下,但是没有钩子是唯一知道按键的程序。

我如何监听键盘事件,同时仍允许其他应用程序查看这些键盘事件?

我认为可能会设置允许LowLevelKeyboardProc执行此操作,但我没有找到任何设置。

0 个答案:

没有答案