8

我已经搜索了这个问题，我发现了很多答案，为我的问题找到解决方案并不难。但是，我有奇怪的经历，我不知道为什么我要求人们给我一些建议。这是我的代码：

    void SetThread()
    {
        for (int i = 0; i < _intArrayLength; i++)
        {
            Console.Write(string.Format("SetThread->i: {0}\r\n", i));
            _th[i] = new Thread(new ThreadStart(() => RunThread(i)));
            _th[i].Start();
        }
    }

    void RunThread(int num)
    {
        Console.Write(string.Format("RunThread->num: {0}\r\n", num));
    }

是的，它们是普通的线程代码。我希望所有线程数组都应该调用 RunThread 方法 10 次。它应该像

SetThread->i: 0
SetThread->i: 1
SetThread->i: 2
SetThread->i: 3
SetThread->i: 4
SetThread->i: 5
SetThread->i: 6
SetThread->i: 7
SetThread->i: 8
SetThread->i: 9
RunThread->num: 0
RunThread->num: 1
RunThread->num: 2
RunThread->num: 3
RunThread->num: 4
RunThread->num: 5
RunThread->num: 6
RunThread->num: 7
RunThread->num: 8
RunThread->num: 9

这就是我所期望的。顺序并不重要。但我得到如下结果。

SetThread->i: 0
SetThread->i: 1
SetThread->i: 2
The thread '<No Name>' (0x18e4) has exited with code 0 (0x0).
The thread '<No Name>' (0x11ac) has exited with code 0 (0x0).
The thread '<No Name>' (0x1190) has exited with code 0 (0x0).
The thread '<No Name>' (0x1708) has exited with code 0 (0x0).
The thread '<No Name>' (0xc94) has exited with code 0 (0x0).
The thread '<No Name>' (0xdac) has exited with code 0 (0x0).
The thread '<No Name>' (0x12d8) has exited with code 0 (0x0).
The thread '<No Name>' (0x1574) has exited with code 0 (0x0).
The thread '<No Name>' (0x1138) has exited with code 0 (0x0).
The thread '<No Name>' (0xef0) has exited with code 0 (0x0).
SetThread->i: 3
RunThread->num: 3
RunThread->num: 3
RunThread->num: 3
SetThread->i: 4
RunThread->num: 4
SetThread->i: 5
SetThread->i: 6
RunThread->num: 6
RunThread->num: 6
SetThread->i: 7
RunThread->num: 7
SetThread->i: 8
RunThread->num: 8
SetThread->i: 9
RunThread->num: 9
RunThread->num: 10

我期望的是 RunThread 函数应该携带从 0 到 9 的参数（num）。我无法弄清楚该错误消息是什么。“线程'' ~~等等。有人能给我一些线索吗？

4

2 回答 2

6

您正在循环变量上创建一个闭包- 一个简单的解决方法是只创建一个本地副本，因此您的线程使用所需的值：

void SetThread()
    {
        for (int i = 0; i < _intArrayLength; i++)
        {
           int currentValue = i;
            Console.Write(string.Format("SetThread->i: {0}\r\n", i));
            _th[i] = new Thread(() => RunThread(currentValue));
            _th[i].Start();
        }
    }
于 2013-08-12T00:52:39.037 回答
3

您可能希望像这样更改代码以使用ParameterizedThreadStart委托：

    for (int i = 0; i < _intArrayLength; i++)
    {
        Console.Write(string.Format("SetThread->i: {0}\r\n", i));
        _th[i] = new Thread((a) => RunThread((int)a));
        _th[i].Start(i);
    }

否则，从您的线程入口点委托中() => RunThread(i)，您正在从父主线程的上下文访问变量i，这可能会在您的新线程启动之前发生变化。

于 2013-08-12T00:48:16.560 回答