Winform窗体拖动

private void panelControl1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                currentFormWidth = this.Width;
                currentFormWidth = this.Height;
                isMouseDown = true;
                mouseOffset = new Point(MousePosition.X - this.Location.X, MousePosition.Y - this.Location.Y);
                this.Cursor = Cursors.SizeAll;
            }
        }

        private void panelControl1_MouseEnter(object sender, EventArgs e)
        {
            isMouseEnter = true;
        }

        private void panelControl1_MouseLeave(object sender, EventArgs e)
        {
            Point p = MousePosition;
            if (p.X - 10 <= this.Left || p.X + 10 >= this.Left + currentFormWidth || p.Y - 10 <= this.Top || p.Y + 10 >= this.Bottom)
            {
                isMouseEnter = false;
            }
        }

        private void panelControl1_MouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown == true)
            {
                Point old = this.Location;
                this.Location = getMiniBallMoveLocation();
            }
        }

        private void panelControl1_MouseUp(object sender, MouseEventArgs e)
        {
            isMouseDown = false;
            this.Cursor = Cursors.Default;
        }

        private Point getMiniBallMoveLocation()
        {
            int x = MousePosition.X - mouseOffset.X;
            int y = MousePosition.Y - mouseOffset.Y;
            return new Point(x, y);
        }