使用List <Thread>管理线程

Question

我正在尝试在c#中实现多线程.

基本思路是:

1. 将会有很多线程进程调用一个函数,并且每个线程都不会按顺序调用它们.

2. 我想限制最大线程数运行.

3. 线程完成后,我想调用另一个线程,直到完成所有操作.

所以为了实现这一点,我使用了一个线程列表.对于每一秒,我检查列表是否已满,以及是否有任何线程完成其工作.

这是我的代码:

List<Thread> threadCompany = new List<Thread>();
List<Thread> fireThisGuy = new List<Thread>();
while (i < _finish) {
    if (threadCompany.Count < _MAX_THREAD) {
        Thread worker = new Thread(delegate() {
            CallFunction(i);
        });

        threadCompany.Add(worker);
        i++;
        worker.Start();
    }

    Thread.Sleep(1000); //Wait for a while instead of keep calling if

    foreach (Thread worker in threadCompany) { 
        if (!worker.IsAlive) {
            fireThisGuy.Add(worker); //because threadCompany may not be 
                                     //modified in iteration.
        }
    }

    foreach (Thread worker in fireThisGuy) {
        threadCompany.Remove(worker);
    }
    fireThisGuy.Clear();
}

这有效,但我不认为我在这里优雅高效,如何改进我的代码呢？

Answer 1

这不是解决问题的正确方法.您不需要保留线程列表,只需在所有线程完成运行时通知应用程序.

这是一种处理问题的可能方法,使用SynchronizationContext在执行完成时通知主线程,没有任何类型的等待周期.

public class OwnerClass
{
    private SynchronizationContext syncContext;
    private int count;
    private int completedCount;

    // This event will be raised when all thread completes
    public event EventHandler Completed;

    public OwnerClass() :
        this(SynchronizationContext.Current)
    {
    }

    public OwnerClass(SynchronizationContext context)
    {
        if (context == null)
            throw new ArgumentNullException("context");
        this.syncContext = context;
    }

    // Call this method to start running
    public void Run(int threadsCount)
    {
        this.count = threadsCount; 
        for (int i = 0; i < threadsCount; ++i)
        {
            ThreadPool.QueueUserWorkItem(this.ThreadFunc, null);
        }
    }

    private void ThreadFunc(object threadContext)
    {
        Thread.Sleep(1000); /// my long and complicated function

        if (Interlocked.Increment(ref this.completedCount) >= this.count)
        {
            this.syncContext.Post(OnCompleted, null);
        }
    }

    protected virtual void OnCompleted(object state)
    {
        var handler = this.Completed;
        if (handler != null)
            handler(this, EventArgs.Empty);
    }
}

如果您只是想在多处理器中运行,可以为每个处理器分配一个线程,您可以使用它 Parallel.For