【学习笔记】C#之利用hook实现拾色器功能

C#之利用hook实现拾色器功能

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一、HOOK的使用

引用dll实现对hook的调用，对鼠标操作进行全局监控。

 		[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(int 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);

回调的函数部分代码

   private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
        {
   
            if (nCode >= 0 && wParam == (IntPtr)WM_LBUTTONDOWN)
            {
   
                //返回的数据类型
                MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
                Console.WriteLine($"Mouse Clicked at X: {
     hookStruct.pt.x}, Y: {
     hookStruct.pt.y},鼠标事件：{
     hookStruct.mouseData}{
     hookStruct.flags}");
                //MessageBox.Show($"Mouse Clicked at X: {hookStruct.pt.x}, Y: {hookStruct.pt.y}");


                MyEvent?.Invoke(this, EventArgs.Empty);
            }
            return CallNextHookEx(_hookID, nCode, wParam, lParam);
        }

二、取色的dll调用的关键引用

        [DllImport("user32.dll")]//取设备场景 
        private static extern IntPtr GetDC(IntPtr hwnd);//返回设备场景句柄 
        [DllImport("gdi32.dll")]//取指定点颜色 
        private static extern int GetPixel(IntPtr hdc, Point p);

三、取色部分代码

  private void Form1_Load(object sender, EventArgs e)
        {
   
            tim = new Timer() {
    Interval = 1 };
            tim.Tick += delegate
            {
   
                Point p = new Point(MousePosition.X, MousePosition.Y);//取置顶点坐标 
                IntPtr hdc = GetDC(new IntPtr(0));//取到设备场景(0就是全屏的设备场景) 
                int c = GetPixel(hdc, p);//取指定点颜色 
                r = (c & 0xFF);//转换R 
                g = (c & 0xFF00) / 256;//转换G 
                b = (c & 0xFF0000) / 65536;//转换B 
                textBox1.Text = $"{