检测窗体C#外部的鼠标单击

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

public class MouseClickDetector
{
    private delegate IntPtr LowLevelMouseProc(int nCode, IntPtr wParam, IntPtr lParam);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelMouseProc 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);

    [DllImport("user32.dll")]
    private static extern bool GetCursorPos(out POINT lpPoint);

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

    private const int WH_MOUSE_LL = 14;
    private const int WM_LBUTTONDOWN = 0x0201;

    private IntPtr _hookID = IntPtr.Zero;

    public void Start()
    {
        _hookID = SetHook(MouseHookCallback);
    }

    public void Stop()
    {
        UnhookWindowsHookEx(_hookID);
    }

    private IntPtr SetHook(LowLevelMouseProc proc)
    {
        using (var curProcess = System.Diagnostics.Process.GetCurrentProcess())
        using (var curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_MOUSE_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    private IntPtr MouseHookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (nCode >= 0 && wParam == (IntPtr)WM_LBUTTONDOWN)
        {
            POINT cursorPos;
            GetCursorPos(out cursorPos);

            Rectangle screenBounds = Screen.PrimaryScreen.Bounds;
            if (cursorPos.X < screenBounds.Left || cursorPos.X > screenBounds.Right ||
                cursorPos.Y < screenBounds.Top || cursorPos.Y > screenBounds.Bottom)
            {
                // 用户在窗体外部进行了鼠标单击操作
                // 执行相应的操作，例如隐藏或关闭窗体
                // 例如：this.Hide();
            }
        }

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

public class Program
{
    private static MouseClickDetector _mouseClickDetector;

    public static void Main()
    {
        _mouseClickDetector = new MouseClickDetector();
        _mouseClickDetector.Start();

        // 程序继续执行其他逻辑
        // 例如：Application.Run(new MainForm());

        Application.Run();
        
        _mouseClickDetector.Stop();
    }
}