如左图，是我运行出来的矩形，运行出来之后 我想能通过鼠标移动点，使矩形变形了，如右图所示……求指教

也许你该画的不是矩形，而是画点，以及点到点之间的连线

我现在已经运行出来了这个矩形，但是不知道该如何编写移动矩形的点的代码，好像要用到鼠标的MouseDown事件，求指教……

思路：
假设图示的九个点命名如下：
11  12  13
21  22  23
31  32  33
分三种情况
1，角点11 13 31  33
2，边点12 21 23  32
3，中心点  22
假设拖动11则相应要调用画图函数连线11-12，11-21；
其余以此类推；

恩恩，但是我不会写代码……不知道怎么写其他的点随之变化，也就是你说的调用其他的点的连线函数  能给我举一个例子么，就写一下一个点移动，另外的点都随着变化的代码，不用 写所有的九个点，就写其中一个的就行了，谢谢你啊……我真的好急，我已经想好几天了，就是不会

  private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics graphics = this.CreateGraphics();
            graphics.Clear(Color.White);
            Pen blackpen = new Pen(Color.Black, 3);

            Point point1 = new Point(100, 100);
            Point point2 = new Point(100, 200);
            Point point3 = new Point(100, 300);
            Point point4 = new Point(100, 400);
            Point point5 = new Point(300, 100);
            Point point6 = new Point(500, 100);
            Point point7 = new Point(700, 100);
            Point point8 = new Point(900, 100);
            Point point9 = new Point(300, 200);
            Point point10 = new Point(500, 200);
            Point point11 = new Point(700, 200);
            Point point12 = new Point(900, 200);
            Point point13 = new Point(300, 300);
            Point point14 = new Point(500, 300);
            Point point15 = new Point(700, 300);
            Point point16 = new Point(900, 300);
            Point point17 = new Point(300, 400);
            Point point18 = new Point(500, 400);
            Point point19 = new Point(700, 400);
            Point point20 = new Point(900, 400);
            Point[] p1 = { point1, point2 };
            graphics.DrawPolygon(blackpen, p1);//两点之间分别连接直线
            Point[] p2 = { point3, point2 };
            graphics.DrawPolygon(blackpen, p2);
            Point[] p3 = { point3, point4 };
            graphics.DrawPolygon(blackpen, p3);
            Point[] p4 = { point4, point17 };
            graphics.DrawPolygon(blackpen, p4);
            Point[] p5 = { point17, point13 };
            graphics.DrawPolygon(blackpen, p5);
            Point[] p6 = { point13, point9 };
            graphics.DrawPolygon(blackpen, p6);
            Point[] p7 = { point9, point5 };
            graphics.DrawPolygon(blackpen, p7);
            Point[] p8 = { point3, point13 };
            graphics.DrawPolygon(blackpen, p8);
            Point[] p9 = { point2, point9 };
            graphics.DrawPolygon(blackpen, p9);
            Point[] p10 = { point1, point5 };
            graphics.DrawPolygon(blackpen, p10);
            Point[] p11 = { point17, point18 };
            graphics.DrawPolygon(blackpen, p11);
            Point[] p12 = { point13, point14 };
            graphics.DrawPolygon(blackpen, p12);
            Point[] p13 = { point9, point10 };
            graphics.DrawPolygon(blackpen, p13);
            Point[] p14 = { point5, point6 };
            graphics.DrawPolygon(blackpen, p14);
            Point[] p15 = { point18, point14 };
            graphics.DrawPolygon(blackpen, p15);
            Point[] p16 = { point10, point14 };
            graphics.DrawPolygon(blackpen, p16);
            Point[] p17 = { point10, point6 };
            graphics.DrawPolygon(blackpen, p17);
            Point[] p18 = { point18, point19 };
            graphics.DrawPolygon(blackpen, p18);[local]1[/local][local]1[/local]
            Point[] p19 = { point15, point14 };
            graphics.DrawPolygon(blackpen, p19);
            Point[] p20 = { point10, point11 };
            graphics.DrawPolygon(blackpen, p20);
            Point[] p21 = { point6, point7 };
            graphics.DrawPolygon(blackpen, p21);
            Point[] p22 = { point19, point20 };
            graphics.DrawPolygon(blackpen, p22);
            Point[] p23 = { point15, point16 };
            graphics.DrawPolygon(blackpen, p23);
            Point[] p24 = { point11, point12 };
            graphics.DrawPolygon(blackpen, p24);
            Point[] p25 = { point7, point8 };
            graphics.DrawPolygon(blackpen, p25);
            Point[] p26 = { point19, point15 };
            graphics.DrawPolygon(blackpen, p26);
            Point[] p27 = { point15, point11 };
            graphics.DrawPolygon(blackpen, p27);
            Point[] p28 = { point11, point7 };
            graphics.DrawPolygon(blackpen, p28);
            Point[] p29 = { point16, point20 };
            graphics.DrawPolygon(blackpen, p29);
            Point[] p30 = { point16, point12 };
            graphics.DrawPolygon(blackpen, p30);
            Point[] p31 = { point8, point12 };
            graphics.DrawPolygon(blackpen, p31);
            SolidBrush redbrush = new SolidBrush(Color.Red);//绘制曲线经过的点
            graphics.FillEllipse(redbrush, new Rectangle(100, 100, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(100, 200, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(100, 300, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(100, 400, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(300, 100, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(500, 100, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(700, 100, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(900, 100, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(300, 200, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(300, 300, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(300, 400, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(500, 200, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(500, 300, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(500, 400, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(700, 200, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(700, 300, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(700, 400, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(900, 200, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(900, 300, 5, 5));
            graphics.FillEllipse(redbrush, new Rectangle(900, 400, 5, 5));
        }