blocks|key|4593416|text|您可以创建许多任务，如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4593417|List<Task>+TaskList+=+new+List<Task>();
foreach(...)
{
+++var+LastTask+=+new+Task(SomeFunction);
+++LastTask.Start();
+++TaskList.Add(LastTask);
}

Task.WaitAll(TaskList.ToArray());|code-block|syntax|javascript|4593418|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could create many tasks like:

<pre><code>List&lt;Task&gt; TaskList = new List&lt;Task&gt;();
foreach(...)
{
 var LastTask = new Task(SomeFunction);
 LastTask.Start();
 TaskList.Add(LastTask);
}

Task.WaitAll(TaskList.ToArray());
</code></pre>

blocks|key|4593447|text|我见过的最好的选择是下面的扩展方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4593448|public+static+Task+ForEachAsync<T>(this+IEnumerable<T>+sequence,+Func<T,+Task>+action)+{
++++return+Task.WhenAll(sequence.Select(action));
}|code-block|syntax|javascript|4593449|这样叫它：|4593450|await+sequence.ForEachAsync(item+=>+item.SomethingAsync(blah));|4593451|或者使用异步lambda：|4593452|await+sequence.ForEachAsync(async+item+=>+{
++++var+more+=+await+GetMoreAsync(item);
++++await+more.FrobbleAsync();
});|4593453|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The best option I've seen is the following extension method:

<pre><code>public static Task ForEachAsync&lt;T&gt;(this IEnumerable&lt;T&gt; sequence, Func&lt;T, Task&gt; action) {
 return Task.WhenAll(sequence.Select(action));
}
</code></pre>

Call it like this:

<pre><code>await sequence.ForEachAsync(item =&gt; item.SomethingAsync(blah));
</code></pre>

Or with an async lambda:

<pre><code>await sequence.ForEachAsync(async item =&gt; {
 var more = await GetMoreAsync(item);
 await more.FrobbleAsync();
});
</code></pre>

blocks|key|4593482|text|当我需要同时加载数据并将其放入变量时，我通常会发现自己的另一个answer...but，例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4593483|var+cats+=+new+List<Cat>();
var+dog+=+new+Dog();

var+loadDataTasks+=+new+Task[]
{
++++Task.Run(async+()+=>+cats+=+await+LoadCatsAsync()),
++++Task.Run(async+()+=>+dog+=+await+LoadDogAsync())
};

try
{
++++await+Task.WhenAll(loadDataTasks);
}
catch+(Exception+ex)
{
++++//+handle+exception
}|code-block|syntax|javascript|4593484|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Yet another answer...but I usually find myself in a case, when I need to load data simultaneously and put it into variables, like:

<pre><code>var cats = new List&lt;Cat&gt;();
var dog = new Dog();

var loadDataTasks = new Task[]
{
 Task.Run(async () =&gt; cats = await LoadCatsAsync()),
 Task.Run(async () =&gt; dog = await LoadDogAsync())
};

try
{
 await Task.WhenAll(loadDataTasks);
}
catch (Exception ex)
{
 // handle exception
}
</code></pre>

blocks|key|4593530|text|我准备了一段代码，向您展示如何在其中一些场景中使用该任务。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4593531|++++//+method+to+run+tasks+in+a+parallel+
++++public+async+Task+RunMultipleTaskParallel(Task[]+tasks)+{

++++++++await+Task.WhenAll(tasks);
++++}
++++//+methode+to+run+task+one+by+one+
++++public+async+Task+RunMultipleTaskOneByOne(Task[]+tasks)
++++{
++++++++for+(int+i+=+0;+i+<+tasks.Length+-+1;+i%2B%2B)
++++++++++++await+tasks[i];
++++}
++++//+method+to+run+i+task+in+parallel+
++++public+async+Task+RunMultipleTaskParallel(Task[]+tasks,+int+i)
++++{
++++++++var+countTask+=+tasks.Length;
++++++++var+remainTasks+=+0;
++++++++do
++++++++{
++++++++++++int+toTake+=+(countTask+<+i)+?+countTask+:+i;
++++++++++++var+limitedTasks+=+tasks.Skip(remainTasks)
++++++++++++++++++++++++++++++++++++.Take(toTake);
++++++++++++remainTasks+%2B=+toTake;
++++++++++++await+RunMultipleTaskParallel(limitedTasks.ToArray());
++++++++}+while+(remainTasks+<+countTask);
++++}|code-block|syntax|javascript|4593532|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I prepared a piece of code to show you how to use the task for some of these scenarios. 

<pre><code> // method to run tasks in a parallel 
 public async Task RunMultipleTaskParallel(Task[] tasks) {

 await Task.WhenAll(tasks);
 }
 // methode to run task one by one 
 public async Task RunMultipleTaskOneByOne(Task[] tasks)
 {
 for (int i = 0; i &lt; tasks.Length - 1; i++)
 await tasks[i];
 }
 // method to run i task in parallel 
 public async Task RunMultipleTaskParallel(Task[] tasks, int i)
 {
 var countTask = tasks.Length;
 var remainTasks = 0;
 do
 {
 int toTake = (countTask &lt; i) ? countTask : i;
 var limitedTasks = tasks.Skip(remainTasks)
 .Take(toTake);
 remainTasks += toTake;
 await RunMultipleTaskParallel(limitedTasks.ToArray());
 } while (remainTasks &lt; countTask);
 }
</code></pre>

blocks|key|87355|text|如果您使用的是async/await+pattern，则可以并行运行多个任务，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|87356|public+async+Task+DoSeveralThings()
{
++++//+Start+all+the+tasks
++++Task+first+=+DoFirstThingAsync();
++++Task+second+=+DoSecondThingAsync();

++++//+Then+wait+for+them+to+complete
++++var+firstResult+=+await+first;
++++var+secondResult+=+await+second;
}|code-block|syntax|javascript|87357|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/^0|7|J|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

If you're using the <a href="https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/" rel="nofollow noreferrer">async/await pattern</a>, you can run several tasks in parallel like this:
<pre class="lang-cs prettyprint-override"><code>public async Task DoSeveralThings()
{
 // Start all the tasks
 Task first = DoFirstThingAsync();
 Task second = DoSecondThingAsync();

 // Then wait for them to complete
 var firstResult = await first;
 var secondResult = await second;
}
</code></pre>

I need to run multiple async tasks in a console application, and wait for them all to complete before further processing.

There's many articles out there, but I seem to get more confused the more I read. I've read and understand the basic principles of the Task library, but I'm clearly missing a link somewhere.

I understand that it's possible to chain tasks so that they start after another completes (which is pretty much the scenario for all the articles I've read), but I want all my Tasks running at the same time, and I want to know once they're all completed.

What's the simplest implementation for a scenario like this?

Running multiple async tasks and waiting for them all to complete

我需要在控制台应用程序中运行多个异步任务，并在进一步处理之前等待它们全部完成。有很多文章，但我读得越多，似乎就越困惑。我已经阅读并理解了任务库的基本原理，但我显然缺少一个链接。我知道可以链接任务，以便它们在另一个任务完成后开始(这几乎就是我读过的所有文章的情况)，但我希望我的所有任务同时运行，并且我想知道它们都完成后的...

问运行多个异步任务并等待它们全部完成
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问运行多个异步任务并等待它们全部完成EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问运行多个异步任务并等待它们全部完成
EN