可.NET任务实例运行期间外出的范围有多大？ [英] Can .NET Task instances go out of scope during run?

问题描述

如果我有code以下块的方法（使用.NET 4和任务并行库）：

If I have the following block of code in a method (using .NET 4 and the Task Parallel Library):

var task = new Task(() => DoSomethingLongRunning());
task.Start();

和该方法返回，将这项任务超出了范围和被垃圾收集，还是会运行完毕？我还没有发现有任何GCing问题，但要确保我不会自己设置了一个竞争条件与GC。

and the method returns, will that task go out of scope and be garbage collected, or will it run to completion? I haven't noticed any issues with GCing, but want to make sure I'm not setting myself up for a race condition with the GC.

推荐答案

更新：

在我回答这个问题，我发现这不是真的，任务将一直运行到结束（很久以前！） - 有一个小的，比方说，弯道情况下，如果任务可能无法完成。

After I answered this question (a long time ago!) I found out that it's not true that Tasks will always run to completion - there's a small, let's say "corner" case, where tasks may not finish.

这其中的原因是这样的：我已经回答了previously，任务基本上是线程;但他们的背景的主题。当所有前台线程结束后台线程将自动终止。所以，如果你不这样做的任务和程序结束任何东西，有一个机会的任务将无法完成。

The reason for that is this: As I have answered previously, Tasks are essentially threads; but they are background threads. Background threads are automatically aborted when all foreground threads finish. So, if you don't do anything with the task and the program ends, there's a chance the task won't complete.

您应该总是在等待任务。更多信息可以在出色答卷乔恩给我被发现。

You should always await on tasks. More information can be found on the excellent answer Jon gave me.

原文：

任务计划的线程池，这意味着他们基本上threads¹（实际上，它们封装线程）。

Task are scheduled to the ThreadPool, meaning that they are essentially threads¹ (actually, they encapsulate threads).

从主题文档：

有没有必要保留   引用一旦你一个Thread对象   已经开始的线程。线程   继续进行，直到该线程执行   手续齐全。

It is not necessary to retain a reference to a Thread object once you have started the thread. The thread continues to execute until the thread procedure is complete.

所以，没有，就没有必要保留一个引用。

So, no, there is no need to retain a reference to it.

此外，文档指出preferred的方式来创建一个任务是使用它的工厂：

Also, the documentation states that the preferred way to create a Task is to use it's factory:

您还可以使用StartNew方法   创建并且在一个启动一个任务   操作。这是preferred方式   创建和如果建立开始任务   和调度不必是   分离（...）

You can also use the StartNew method to create and start a task in one operation. This is the preferred way to create and start tasks if creation and scheduling do not have to be separated (...)

希望它帮助。

¹因此到文档：

一个任务重presents异步   操作，并在某些方面它   类似于创建一个新的线程   或线程池工作项目，但在   更高层次的抽象。

A task represents an asynchronous operation, and in some ways it resembles the creation of a new thread or ThreadPool work item, but at a higher level of abstraction.

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