请问怎么在一个panel里画一个圆？

[callmesai]

例如在panel1上画一个圆心为(x,y)半径为z的圆~~

请问怎么才能做到？谢谢啦~~~

[wuyi8808]

using System;
using System.Drawing;
using System.Windows.Forms;

class Form1 : Form
{
  Form1()
  {
    Panel panel1  = new Panel();
    panel1.Parent = this;
    panel1.Dock   = DockStyle.Fill;
    panel1.Paint += delegate(object o, PaintEventArgs e)
    {
      // 画一个圆心为(x,y)半径为z的圆
      float x = 80;
      float y = 90;
      float z = 50;
      e.Graphics.DrawEllipse(Pens.Red, x - z, y - z, z * 2, z * 2);
    };
  }
  
  static void Main()
  {
    Application.Run(new Form1());
  }
}

[cppfaq]

int x = 100;
            int y = 100;
            int z = 40;
            Graphics g = CreateGraphics();
            Pen pen = new Pen(Color.Red, 2);
            
            g.DrawEllipse(pen, x - z, y - z, 2 * z , 2* z);
            g.Flush();
            g.Dispose();

[kbtjh]

private void panel1_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.DrawEllipse( new Pen (Color.Yellow ,1 ) ,5,5,150,150);
}
你看看吧!!

[wuyi8808]

如果要画实心圆，则用 FillEllipse() 方法：

using System;
using System.Drawing;
using System.Windows.Forms;

class Form1 : Form
{
  Form1()
  {
    Panel panel1  = new Panel();
    panel1.Parent = this;
    panel1.Dock   = DockStyle.Fill;
    panel1.Paint += delegate(object o, PaintEventArgs e)
    {
      // 画一个圆心为(x,y)半径为z的实心圆
      float x = 80;
      float y = 90;
      float z = 20;
      e.Graphics.FillEllipse(new SolidBrush(Color.Blue), x - z, y - z, z * 2, z * 2);
    };
  }
  
  static void Main()
  {
    Application.Run(new Form1());
  }
}

[wenblue7]

[Quote=引用 1 楼 wuyi8808 的回复:]
C# codeusing System;
using System.Drawing;
using System.Windows.Forms;

class Form1 : Form
{
Form1()
{
Panel panel1 = new Panel();
panel1.Parent = this;
panel1.Dock = DockStyle.Fill;
panel1.Paint += delegate(object o, PaintEventArgs e)
{
// 画一个圆心为(x,y)半径为z的圆
float x = 80;
float y = 90;
float z = 50;
e.Graphics.D…
[/Quote]
方法很好啊

[AdaEniac]

在panel的Paint方法中，写上下面的代码...
private int x = 100;
private int y = 100;
private int z = 50;
private void panel1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawEllipse(new Pen(Color.Green, 2), x - z, y - z, 2 * z, 2 * z);

//下面部分可以省略，只是方便验证
e.Graphics.DrawLine(new Pen(Color.Blue, 1), 0, 0, x, y);
e.Graphics.DrawLine(new Pen(Color.Blue, 1), 0, y, x, y);
e.Graphics.DrawLine(new Pen(Color.Blue, 1), x, 0, x, y);
}

[callmesai]

谢谢楼上各位~~画出圆了~~但是为什么刷新一下就没有啦？

[AdaEniac]

但是为什么刷新一下就没有啦？

你是怎么刷新的,我这边很正常啊...
OnPaint 是时时画的，别说你刷新，你就是切换界面它就会重新画一次.

[wdz0909]

GDI+画图一般是在内存中画，直接在窗体上画刷新就会没了。
内存中画图方式:
按钮单击事件中写一下代码
Bitmap bmp = new Bitmap(400,500);
Graphic g = Graphic.FromImage(bmp);
g.DrawEllipse(...); //参数省略


然后呢在
panel中放个图片控件
pic.Image = bmp;


差不多就这个意思

[baiyunyinv]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            Panel panel1 = new Panel();
            panel1.Parent = this;
            panel1.Dock = DockStyle.Fill;
            //匿名方法
            panel1.Paint += delegate(object sender, PaintEventArgs e)
            {
                // 画一个圆心为(x,y)半径为z的圆
                float x = 80;
                float y = 90;
                float z = 50;
                e.Graphics.DrawEllipse(Pens.Red, x - z, y - z, z * 2, z * 2);
            };
        }
    }
}