winfrom drawLine 问题
点一下button 动态增加一个Panel并且 可以连续点Button 生成N个Panel，Panel跟button生成直线并连接，问题：我点别的菜单、在进入此界面 直线不在了，生成Panel还在、线条怎么不在了呢 请教高手 是不是做的有问题！ 此界面只有一个按钮跟按钮事件
代码如下：

C# code

static int x, y = 0;        private Panel controlsPanel()        {            #region Panel            Panel p1 = new Panel(); //p1最外层            //p1.BackColor = System.Drawing.SystemColors.ActiveCaption;            p1.Width = 90;            p1.Height = 90;            p1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;            p1.Location = new System.Drawing.Point(x, y);                       #endregion            #region Button            Button btn1 = new Button();            btn1.Text = "温湿度";            btn1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;            btn1.Width = 90;            btn1.Height = 90;            btn1.Image = global::Platform.Client.Properties.Resources.l1_bg;            p1.Controls.Add(btn1);                        #endregion            x += p1.Width + 2;            if (x + p1.Width > this.panel1.ClientRectangle.Width)            {                x = 0;                y += panel1.Height-p1.Height;            }                        drawLine(x - (p1.Width / 2), y + p1.Height, 393, 228);                        return p1;        }        private void drawLine(int x1,int y1,int x2,int y2)        {                        IntPtr hwnd = new IntPtr();            hwnd = this.panel1.Handle;            Graphics newGraphics = Graphics.FromHwnd(hwnd);            Point myStartPoint = new Point(x1, y1);            Point myEndPoint = new Point(x2, y2);            newGraphics.DrawLine(new Pen(Color.Red, 3), myStartPoint, myEndPoint);            newGraphics.Dispose();        }        private void button1_Click(object sender, EventArgs e)        {            this.panel1.Controls.Add(controlsPanel());        }

[解决办法]


你的panel有很多个，互相之间连线，怎么可能会在某一个panel的paint里画线呢？你是把鸡蛋装在篮子里，不是把篮子装在鸡蛋里。。。
[解决办法]

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引用:
static int x, y = 0;
List<int[]> points = new List<int[]>();
private Panel controlsPanel()
{
#region Panel
Panel p1 = new Panel(); //p1最外层
//p1.BackColor = System.Drawing.SystemColo……