如何使用任务在一个线程中执行循环的每个迭代? [英] How to execute each iteration of the loop in one thread with task?

问题描述

我有一个检查某些数据的方法，我想知道如何在不同的线程中检查这些数据.我正在使用任务和异步/等待模式.

I have a method that check some data and I would like to know how to check this data in differents threads. I am using task and async/await pattern.

private bool my myCheckMethod(List<long> paramData)
{
     //code that check the information in the list
}


private void mainMethod()
{
    //1.- get data from the data base
    //2.- i group the data from the database in many lists.

    foreach(list<List<long>> iterator in myListOfLists)
    {
          myCheckMethod(itrator);
    }
}

但是我希望myCheckMethod不能一次只执行一个，而是要使用任务来同时执行多个任务.我认为这会花更少的时间.

But I would like that the myCheckMethod not execute only one at time, but to use tasks to execute many at same time. I think that it would take less time.

但是，我不知道该怎么做.我尝试这样的事情:

However, I don't know well how to do that. I try something like that:

private void mainMethod()
{
    //1.- get data from the data base
    //2.- i group the data from the database in many lists.

    string initTime = System.DateTime.String();
    foreach(list<List<long>> iterator in myListOfLists)
    {
          myCheckMethod(itrator);
    }

    string endTime = System.DateTime.String();
}

我想在开始检查以及检查所有列表时获得信息.

I would like to have information when the check is started and when all the lists are checked.

我尝试这样的事情:

private void mainMethod()
    {
        //1.- get data from the data base
        //2.- i group the data from the database in many lists.

        string startTime = System.DateTime.String();
        foreach(list<List<long>> iterator in myListOfLists)
        {
             TaskEx.Run(() =>
             {
                myCheckMethod(itrator);
             });
        }

        string endTime = System.DateTime.String();
    }

但是在这种情况下，开始时间和结束时间是相同的，因为我不等待任务.因此，我尝试了另一种选择:

But in this case start time and end time is the same, because I don't await the task. So I try this other option:

private void mainMethod()
    {
        //1.- get data from the data base
        //2.- i group the data from the database in many lists.

        string startTime = System.DateTime.String();
        foreach(list<List<long>> iterator in myListOfLists)
        {
             TaskEx.Run(() =>
             {
                myCheckMethod(itrator);
             }).wait();
        }

        string endTime = System.DateTime.String();
    }

但是在这种情况下，一次只能执行一个myCheckMethod，因为我想完成一个myCheckMethod来继续下一次迭代.

But in this case only is executed one myCheckMethod at the same time, because I am wating to finish one to continue with the next iteration.

那我怎样才能同时执行许多检查方法呢?

So how can I execute many check methods at the same time?

推荐答案

var sw = Stopwatch.StartNew();
var pendingTasks =
  myListOfLists
    .Select(iterator => TaskEx.Run(() => myCheckMethod(iterator))).ToArray();
Task.WaitAll(pendingTasks);
var elapsedTime = sw.Elapsed;

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