无边窗体的移动

        #region 移动无边窗体
        [DllImport("user32.dll")]
        public static extern bool ReleaseCapture();
        [DllImport("user32.dll")]
        public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);
        public const int WM_SYSCOMMAND = 0x0112;
        public const int SC_MOVE = 0xF010;
        public const int HTCAPTION = 0x0002;
        #endregion
        #region 事件
        private void FrmLogin_MouseDown(object sender, MouseEventArgs e)
        {
            ReleaseCapture();
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);
        }
        #endregion

        bool beginMove = false;//初始化
        int currentXPosition;
        int currentYPosition;
        //鼠标移动事件
        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (beginMove)
            {
                this.Left += MousePosition.X - currentXPosition;//根据鼠标x坐标确定窗体的左边坐标x
                this.Top += MousePosition.Y - currentYPosition;//根据鼠标的y坐标窗体的顶部，即Y坐标
                currentXPosition = MousePosition.X;
                currentYPosition = MousePosition.Y;
            } 
        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            beginMove = true;
            currentXPosition = MousePosition.X;//鼠标的x坐标为当前窗体左上角x坐标
            currentYPosition = MousePosition.Y;//鼠标的y坐标为当前窗体左上角y坐标 
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            beginMove = false;//停止移动 
        }

        private void Form1_MouseLeave(object sender, EventArgs e)
        {
            currentXPosition = 0; //设置初始状态
            currentYPosition = 0;
            beginMove = false;
        }