如何在 WPF 窗口外捕获 MouseUp 事件？

Question

主题都在标题中。对不起，如果它是重复的，我真的在 SO 上找不到任何东西。

Answer 1

嗯，非常感谢 Anatoliy Nikolaev 引导我朝着正确的方向前进！ article 对我帮助很大，而 answer 对于使文章中的代码工作很有用。这就是我现在拥有的：

internal static class MouseHook
{
    private delegate int HookProc(int nCode, int wParam, IntPtr lParam);
    private static int _mouseHookHandle;
    private static HookProc _mouseDelegate;

    private static event MouseUpEventHandler MouseUp;
    public static event MouseUpEventHandler OnMouseUp
    {
        add
        {
            Subscribe();
            MouseUp += value;
        }
        remove
        {
            MouseUp -= value;
            Unsubscribe();
        }
    }

    private static void Unsubscribe()
    {
        if (_mouseHookHandle != 0)
        {
            int result = UnhookWindowsHookEx(_mouseHookHandle);
            _mouseHookHandle = 0;
            _mouseDelegate = null;
            if (result == 0)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode);
            }
        }
    }

    private static void Subscribe()
    {
        if (_mouseHookHandle == 0)
        {
            _mouseDelegate = MouseHookProc;
            _mouseHookHandle = SetWindowsHookEx(WH_MOUSE_LL,
                _mouseDelegate,
                GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName),
                0);
            if (_mouseHookHandle == 0)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode);
            }
        }
    }

    private static int MouseHookProc(int nCode, int wParam, IntPtr lParam)
    {
        if (nCode >= 0)
        {
            MSLLHOOKSTRUCT mouseHookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
            if (wParam == WM_LBUTTONUP)
            {
                if (MouseUp != null)
                {
                    MouseUp.Invoke(null, new Point(mouseHookStruct.pt.x, mouseHookStruct.pt.y));
                }
            }
        }
        return CallNextHookEx(_mouseHookHandle, nCode, wParam, lParam);
    }     

    private const int WH_MOUSE_LL = 14;
    private const int WM_LBUTTONUP = 0x0202;

    [StructLayout(LayoutKind.Sequential)]
    private struct POINT
    {
        public int x;
        public int y;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct MSLLHOOKSTRUCT
    {
        public POINT pt;
        public uint mouseData;
        public uint flags;
        public uint time;
        public IntPtr dwExtraInfo;
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto,
        CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    private static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);

    [DllImport("user32.dll", CharSet = CharSet.Auto,
       CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    private static extern int UnhookWindowsHookEx(int idHook);

    [DllImport("user32.dll", CharSet = CharSet.Auto,
         CallingConvention = CallingConvention.StdCall)]
    private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);

    [DllImport("kernel32.dll")]
    public static extern IntPtr GetModuleHandle(string name); 
}

public delegate void MouseUpEventHandler(object sender, Point p);

而且使用起来非常简单：

MouseHook.OnMouseUp += MouseHookMouseUp;