c# - 多线程 C# : Does not return the result as I expected

Question

我是新手，我有一个c#的多线程实现。但结果返回错误。文件 <number.txt>有数字 0 到 1000。但返回值是 1 到 1000。不是 0。请帮助我理解问题。谢谢。

static void Number(int number)
{
    List<string> l_number = new List<string>(File.ReadAllLines("number.txt"));
    Console.WriteLine(l_number[number]);
}

static void Main(string[] args)
{
    List<Thread> l_thread = new List<Thread>();
    int soThread = 10;

    Thread thread1 = new Thread(delegate ()
    {
        var numnum = 0;
        while (true)
        {
            for (int i = 0; i < soThread; i++)
            {
                Thread threadnew = new Thread(delegate ()
                {
                    //Console.WriteLine(numnum);
                    Number(numnum);
                });
                threadnew.Start();
                l_thread.Add(threadnew);
                numnum++;
                Thread.Sleep(100);
            }
            foreach (Thread item in l_thread)
            {
                item.Join();
            }
        }
    });

Answer 1

您正在捕获 numnum - 它不是每个线程，时间意味着它不是捕获时的值 - 它是线程得到调度时的值；尝试为每个范围创建一个变量副本，即

for (int i = 0; i < soThread; i++)
{
    int copy = numnum;
    Thread threadnew = new Thread(delegate ()
    {
        //Console.WriteLine(copy);
        Number(copy);
    });

    // ...
}