private bool isMouseLeftKeyDown = false;        private Point mousePointToClient = new Point();//相对于本窗体鼠标位置        private Point mousePointToScreen = new Point();//相对于屏幕鼠标位置        private void Form_MouseDown(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {
    Control ctrl = sender as Control;                isMouseLeftKeyDown = true;                this.mousePointToClient = new Point(e.X + ctrl.Location.X, e.Y + ctrl.Location.Y);                this.mousePointToScreen = Control.MousePosition;            }        }        private void Form_MouseMove(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left && isMouseLeftKeyDown)            {                this.Top = Control.MousePosition.Y - mousePointToClient.Y;                this.Left = Control.MousePosition.X - mousePointToClient.X;            }        }        private void Form_MouseUp(object sender, MouseEventArgs e)        {            if (e.Button == MouseButtons.Left)            {                isMouseLeftKeyDown = false;                FormClick();            }        }        private void FormClick()        {            //鼠标位置没有发成偏移，视为点击事件            if (mousePointToScreen != Control.MousePosition)                return;            //todo        }