在winfrom中动态添加控件的问题！！！急！！！！！！！！

Question

在按钮的单击事件中            PictureBox picBox = new PictureBox();
            picBox.Width = 260;
            picBox.Height = 80;
            picBox.Left = 20;
            picBox.Top = 20;       
            panel1.Controls.Add(picBox);
           
            Graphics myGrap = picBox.CreateGraphics();
            Pen blackPen = new Pen(Color.Black, 3);
            Point point1 = new Point(100, 100);
            Point point2 = new Point(500, 100);
            myGrap.DrawLine(blackPen, point1, point2);
为什么就显示不出来呢

Answer 1

不是用PictureBox 画图吧？
            PictureBox picBox = new PictureBox();
            picBox.Width = 260;
            picBox.Height = 80;
            picBox.Left = 20;
            picBox.Top = 20;
            picBox.CreateControl();
            panel1.Controls.Add(picBox);
            picBox.ImageLocation = "http://community.csdn.net/images/csdn.gif";
正常，表示创建成功了

Answer 2

不得行  如果PictureBox 不是动态添加的话              
           Graphics myGrap = picBox.CreateGraphics();
            Pen blackPen = new Pen(Color.Black, 3);
            Point point1 = new Point(100, 100);
            Point point2 = new Point(500, 100);
            myGrap.DrawLine(blackPen, point1, point2);
就可以显示出数据来，- -！

Answer 3

private void button1_Click(object sender, EventArgs e)
        {
            PictureBox picBox = new PictureBox();
            picBox.Width = 260;
            picBox.Height = 80;
            picBox.Left = 20;
            picBox.Top = 20;
            picBox.CreateControl();
            panel1.Controls.Add(picBox);
            picBox.ImageLocation = "http://community.csdn.net/images/csdn.gif";
        }        private void button2_Click(object sender, EventArgs e)
        {
            PictureBox picBox = panel1.Controls[0] as PictureBox;
            Graphics myGrap = picBox.CreateGraphics();
            Pen blackPen = new Pen(Color.Black, 3);
            Point point1 = new Point(1, 20);
            Point point2 = new Point(1, 40);
            myGrap.DrawLine(blackPen, point1, point2);
        }

Answer 4

to:rtsp(自命不凡-->专出馊主意) 
   
     - -！ 谢谢 这不是我要的效果，要是这样的话用户会有意见！

Answer 5

PictureBox picBox = new PictureBox();
            picBox.Width = 260;
            picBox.Height = 80;
            picBox.Left = 0;
            picBox.Top = 0;
            panel1.Controls.Add(picBox);
            panel1.Refresh();
            Graphics myGrap = picBox.CreateGraphics();
            Pen blackPen = new Pen(Color.Black, 3);
            Point point1 = new Point(1, 1);
            Point point2 = new Point(260, 80);
            myGrap.DrawLine(blackPen, point1, point2);

Answer 6

参考一下我的代码吧，不过是vb的语法，C#的我也不怎么会写，呵呵Public Class Form1    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim pic As New PictureBox
        With pic
            .Location = New Point(100, 50)
            .Size = New Size(200, 200)
            .BorderStyle = BorderStyle.FixedSingle
        End With
        Me.Controls.Add(pic)
        Dim g As Graphics = Me.GetGraphics(pic)
        g.DrawLine(Pens.Red, New Point(0, 0), New Point(pic.Width, pic.Height))
    End Sub    Function GetGraphics(ByRef pic As PictureBox) As Graphics
        Dim bmp As Bitmap = New Bitmap(pic.Width, pic.Height)
        pic.Image = bmp        Dim g As System.Drawing.Graphics = Graphics.FromImage(bmp)
        Return g
    End FunctionEnd Class

Answer 7

to :panel1.Refresh();才是王道 
    忘完了，郁闷！唉！！！