在Task.Run默认TaskCreationOptions [英] Default TaskCreationOptions in Task.Run

问题描述

为什么对于 CreationOptions 的缺省值工作使用 Task.Run <创建/ code>是 DenyChildAttach ，而不是无？

Why the default value for CreationOptions of a Task created using Task.Run is DenyChildAttach rather than None?

有它什么与做工作，新的异步和等待在C＃5.0简单（由$ p $逃跑当前上下文我猜的）当前调度pventing吗？

Has it anything to do with making work with the new async and await in C# 5.0 simpler (by preventing you from escaping current scheduler of current context I guess)?

推荐答案

斯蒂芬Toub介绍了这口井<一个href=\"http://blogs.msdn.com/b/pfxteam/archive/2012/09/22/new-taskcreationoptions-and-taskcontinuationoptions-in-net-4-5.aspx\">in他的博客关于这个问题的。

Stephen Toub explains this well in his blog post on the subject.

家长和孩子的任务时使用有些常见的任务 S IN以并行的方式。请注意，当父工作有一个孩子，父母的完成语义微妙地改变。

Parent and child tasks are somewhat common when using Tasks in a parallel fashion. Note that when a parent Task has a child, the parent's completion semantics change subtly.

父/子任务，使用工作 S IN的异步时尚时，几乎从来没有使用过。在异步的世界里，你有一种逻辑父/子关系时，有一个异步方法调用了另一个，但它不使用父/子任务实际实现

Parent/child tasks are almost never used when using Tasks in an async fashion. In the async world, you have a sort of "logical parent/child relationship" when one async method calls another, but it is not actually implemented using parent/child tasks.

通常一个工作拟用于异步 code未预计有其完成语义变化由子任务附加到它。因此，对于 Task.Run 新缺省值是 DenyChildAttach ，其中prevents的子任务尝试连接。

Usually a Task intended for use in async code is not expecting to have its completion semantics changed by a child task attaching to it. Thus, the new default for Task.Run is DenyChildAttach, which prevents any child tasks attempting to attach.

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