C# API Keybd_event + mouse_event

[DllImport("user32.dll", EntryPoint = "mouse_event")]
        public static extern void mouse_event(
            int dwFlags,
            int dx,
            int dy,
            int cButtons,
            int dwExtraInfo
        );

        [DllImport("user32.dll", EntryPoint = "keybd_event")]
        public static extern void keybd_event(
            byte bVk,
            byte bScan,
            int dwFlags,
            int dwExtraInfo
        );

        const int MOUSEEVENTF_MOVE = 0x0001;      //移动鼠标 
        const int MOUSEEVENTF_LEFTDOWN = 0x0002; //模拟鼠标左键按下 
        const int MOUSEEVENTF_LEFTUP = 0x0004; //模拟鼠标左键抬起 
        const int MOUSEEVENTF_RIGHTDOWN = 0x0008; //模拟鼠标右键按下 
        const int MOUSEEVENTF_RIGHTUP = 0x0010; //模拟鼠标右键抬起 
        const int MOUSEEVENTF_MIDDLEDOWN = 0x0020; //模拟鼠标中键按下 
        const int MOUSEEVENTF_MIDDLEUP = 0x0040;// 模拟鼠标中键抬起 
        const int MOUSEEVENTF_ABSOLUTE = 0x8000; //标示是否采用绝对坐标



        public Form1()
        {
            InitializeComponent();

            int X = 100;
            int Y = 100;

            mouse_event( MOUSEEVENTF_RIGHTDOWN, X , Y , 0, 0);
            mouse_event(MOUSEEVENTF_RIGHTUP, X , Y, 0, 0);

            X += 10;
            Y += 65;
            mouse_event(MOUSEEVENTF_MOVE, X, Y , 0, 0);
            mouse_event(MOUSEEVENTF_LEFTDOWN, X, Y , 0, 0);
            mouse_event(MOUSEEVENTF_LEFTUP, X, Y , 0, 0);

            keybd_event(65, 0, 0, 0);//a
            keybd_event(66, 0, 1, 0);//b
            keybd_event(13, 0, 0, 0);//回车

        }