C#如何在MDIParent窗体里的2个子窗体间画一条连线

Question

C#如何在MDIParent窗体里的2个子窗体间画一条连线，连线以每个子窗体的中心为起点或结束点，当窗体拖动时连线也改变??

Answer 1

用到的代码
出现个问题，一个是只要有base.OnPaint(e)就会出现StackOverflowException异常，去掉的话没有线
        private void MDIParentDevices_Paint(object sender, PaintEventArgs e) //窗体重绘处理
            //protected override void OnPaint(PaintEventArgs e)
        { 
            base.OnPaint(e);
            //Console.WriteLine("daomei");
            DrawAllLines(e);
        }
    private class ControlLists
    {        
       public IntPtr control1;
       public IntPtr control2;
    }
    private static ArrayList DeviceDrawLines = new ArrayList();
    public static void DrawAllLines(PaintEventArgs pe)
    {
        try
        {
            foreach (ControlLists one in DeviceDrawLines)
            {
                Control control1 = Form.FromHandle(one.control1);
                Control control2 = Form.FromHandle(one.control2);
                Point pta = new Point(control1.Location.X + control1.Width / 2, control1.Location.Y + control1.Height / 2);
                Point ptb = new Point(control2.Location.X + control2.Width / 2, control2.Location.Y + control2.Height / 2);
                Random random = new Random();
                Graphics g = pe.Graphics;
                
                Pen p = new Pen(Color.FromArgb(85, random.Next(0, 255), random.Next(0, 255), random.Next(0, 255)), 3);
                g.DrawLine(p, pta, ptb);
            }
        }
        catch (NullReferenceException err)
        {        }

Answer 2

 foreach (ControlLists one in DeviceDrawLines)
            {
                Control control1 = Form.FromHandle(one.control1);
                Control control2 = Form.FromHandle(one.control2);
                Point pta = new Point(control1.Location.X + control1.Width / 2, control1.Location.Y + control1.Height / 2);
                Point ptb = new Point(control2.Location.X + control2.Width / 2, control2.Location.Y + control2.Height / 2);
                Random random = new Random();
                Graphics g = pe.Graphics;
                
                Pen p = new Pen(Color.FromArgb(85, random.Next(0, 255), random.Next(0, 255), random.Next(0, 255)), 3);
                g.DrawLine(p, pta, ptb);
            }同意楼上

Answer 3

其实你可以在MDI主窗体上画。