c#产生随机圆随机半径随机位置

Question

 

Answer 1

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

namespace test
{
    public partial class Form2 : Form
    {
        private Random rnd = new Random();
        public Form2()
        {
            InitializeComponent();
        }
        /// 按钮事件请在按钮上进行绑定，或在InitializeComponent里添加事件
        private void button1_Click(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            if (btn.Text == "开始")
            {
                btn.Text = "结束";
                for (int i = 0; i < 100; i++)
                {
                    Thread th = new Thread(new ThreadStart(DrawCircle));
                    th.Start();
                }
            }
            else
            {
                btn.Text = "开始";
            }
        }
        private void DrawCircle()
        {
            while (true)
            {
                // 线程等待，避免资源消耗过多，窗体其他控件无法响应
                Thread.Sleep(100);
                // 当点击停止按钮后，按钮文字变成开始，线程内检测到按钮文字是开始时，退出线程
                if (button1.Text == "开始")
                {
                    return;
                }
                // 线程内更改窗体内容时，请使用委托
                this.Invoke(new MethodInvoker(delegate
                {
                    // 用随机数设置颜色，位置，大小，并画到窗体上
                    int x = rnd.Next(1, this.Width);
                    int y = rnd.Next(1, this.Height);
                    int w = rnd.Next(3, 20);
                    int h = w;
                    Graphics g = this.CreateGraphics();
                    Pen p = new Pen(Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255)), 2);
                    g.DrawEllipse(p, x, y, w, h);
                }));
            }
        }
    }
}