winform中自定义的窗体移动代码

分为三个事件组成   参考网上代码 

bool formMove = false;//窗体是否移动
        Point formPoint;//记录窗体的位置
      //  private bool p;

        /// <summary>
        /// 鼠标按下
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void frmLogin_MouseDown(object sender, MouseEventArgs e)
        {
            formPoint = new Point();
            int xOffset;
            int yOffset;
            if (e.Button == MouseButtons.Left)
            {
                xOffset = -e.X - SystemInformation.FrameBorderSize.Width;
                yOffset = -e.Y - SystemInformation.CaptionHeight - SystemInformation.FrameBorderSize.Height;
                formPoint = new Point(xOffset, yOffset);
                formMove = true;//开始移动
            }
        }

        /// <summary>
        /// 窗体拖动
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void frmLogin_MouseMove(object sender, MouseEventArgs e)
        {
            if (formMove == true)
            {
                Point mousePos = Control.MousePosition;
                mousePos.Offset(formPoint.X + 3, formPoint.Y + 30);
                Location = mousePos;
            }
        }

        /// <summary>
        /// 鼠标松开
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void frmLogin_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)//按下的是鼠标左键
            {
                formMove = false;//停止移动
            }
        }