winform 设置移动窗体

private Point mouseOffset;
        private bool isMouseDown = false;
        public Form1()
        {
            InitializeComponent();
        }

    

        private void button2_Click(object sender, EventArgs e)
        {
            Close();
        }

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            int yOffset, xOffset;
            if (e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                xOffset = -e.X - SystemInformation.FrameBorderSize.Width;
                yOffset = -e.Y - SystemInformation.CaptionHeight - SystemInformation.FrameBorderSize.Height;
                mouseOffset = new Point(xOffset, yOffset);
                isMouseDown = true;
            }
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            if(e.Button == System.Windows.Forms.MouseButtons.Left)
            {
                isMouseDown = false;
            }
        }

        private void Form1_MouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown)
            {
                Point p = Control.MousePosition;
                p.Offset(mouseOffset.X,mouseOffset.Y);
                Location = p;
            }
        }
    }