c# - 如何并行运行一组函数并等待完成后的结果？

Question

我需要同时异步运行一组繁重的函数并将结果填充到列表中。这是伪代码:

List<TResult> results = new List<TResults>();
List<Func<T, TResult>> tasks = PopulateTasks();

foreach(var task in tasks)
{
    // Run Logic in question
    1. Run each task asynchronously/parallely
    2. Put the results in the results list upon each task completion
}

Console.WriteLine("All tasks completed and results populated");

我需要 foreach block 中的逻辑。你们能帮帮我吗？

我有一些限制:解决方案必须符合 .net 3.5(不是 .net 4，但出于我的知识目的，将不胜感激 .net 4 替代解决方案)

提前致谢。

Answer 1

一个简单的 3.5 实现看起来像这样

List<TResult> results = new List<TResults>();
List<Func<T, TResult>> tasks = PopulateTasks();

ManualResetEvent waitHandle = new ManualResetEvent(false);
void RunTasks()
{
    int i = 0;
    foreach(var task in tasks)
    {
        int captured = i++;
        ThreadPool.QueueUserWorkItem(state => RunTask(task, captured))
    }

    waitHandle.WaitOne();

    Console.WriteLine("All tasks completed and results populated");
}

private int counter;
private readonly object listLock = new object();
void RunTask(Func<T, TResult> task, int index)
{
    var res = task(...); //You haven't specified where the parameter comes from
    lock (listLock )
    {
       results[index] = res;
    }
    if (InterLocked.Increment(ref counter) == tasks.Count)
        waitHandle.Set();
}