当窗体没有边框的时候,可以使用该方法拖动窗体

 

  Point downpoint;
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            downpoint.X = e.X;
            downpoint.Y = e.Y;
        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                this.Location = new Point(this.Location.X + e.X - downpoint.X, this.Location.Y + e.Y - downpoint.Y);
            }
        }