Question

在Form Load的事件处理程序中，我有以下代码

    Panel pHText = new Panel();
    Font myFont = new Font("Arial", 14);
    pHText.Location=new Point(10,10);
    pHText.Size=new Size(200,200);
    pHText.BackColor = Color.White;
    Graphics g = pHText.CreateGraphics();
    g.DrawLine(new Pen(Color.Black), 0, 0, 10, 10);
    g.DrawString("text", myFont, Brushes.Blue, 10, 10);
    Controls.Add(pHText);

白色面板显示在表单中，但那些线条和字符串的图形不是。

Answer 1

您需要在OnPaint事件中绘制面板。你不能看到你的绘图，因为在组件刷新之后它们被重绘 - 但你没有。

Answer 2

此代码将进入表单加载事件

Panel pHText = new Panel();
pHText.Name = "ctrId"; //specify control name, to access it in other parts of your code
pHText.Location = new Point(10, 10);
pHText.Size = new Size(200, 200);
pHText.BackColor = Color.White;
pHText.Paint += paintingUrCtr;//adding onpaint event
Controls.Add(pHText)

添加名为paintingUrCtr的绘画事件。

private void paintingUrCtr(object sender, PaintEventArgs e)
{
        Font myFont = new Font("Arial", 14);
        e.Graphics.DrawLine(new Pen(Color.Black),  0, 0, 10, 10);
        e.Graphics.DrawString("text", myFont, Brushes.Blue, 10, 10);
}

Answer 3

FormLoad是绘制图形的错误位置。尝试在内部使用OnPaint方法重载和e.Graphics。

protected override void OnPaint(PaintEventArgs e)
{
   // If there is an image and it has a location, 
   // paint it when the Form is repainted.
   base.OnPaint(e);
   if(this.picture != null && this.pictureLocation != Point.Empty)
   {
      e.Graphics.DrawImage(this.picture, this.pictureLocation);
   }
}

在Winform中绘制Panel时出现问题

3 个答案: