C# 多线程编程：解决命名空间冲突问题

这些代码无法运行，因为名称为'Thread'的命名空间与C#中的System.Threading.Thread类冲突。需要将命名空间更改为其他名称，例如'ThreadDemo'。同时，需要在Form1类的开头添加以下代码来引用System.Threading命名空间：

using ThreadDemo = System.Threading;

以下是修改后的代码示例：

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

        private void button1_Click(object sender, EventArgs e)
        {
            ThreadDemo.Thread thread1 = new ThreadDemo.Thread(new ThreadDemo.ThreadStart(DoWork));
            ThreadDemo.Thread thread2 = new ThreadDemo.Thread(new ThreadDemo.ThreadStart(DoWork));
            ThreadDemo.Thread thread3 = new ThreadDemo.Thread(new ThreadDemo.ThreadStart(DoWork));

            thread1.Start();
            thread2.Start();
            thread3.Start();

            thread1.Join();
            thread2.Join();
            thread3.Join();

            MessageBox.Show("All threads completed.");
        }
        private void DoWork()
        {
            for (int i = 1; i <= 60; i++)
            {
                // Simulate some work
                ThreadDemo.Thread.Sleep(1000);
            }
        }
    }
}

通过以上修改，您就可以成功运行代码，实现多线程编程的功能。