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

namespace WindowsFormsGDIDrawEllipse
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //创建画布
            Graphics graphics = this.CreateGraphics();
            //创建画笔 
            Pen myPen = new Pen(Color.Black, 3);
            //绘制椭圆
            graphics.DrawEllipse(myPen, 100, 50, 100, 50);
        }
    }
}