是否可以从TPL Task派生以从方法返回更多详细信息？ [英] Is it ok to derive from TPL Task to return more details from method?

问题描述

我的原始方法如下：

string DoSomeWork();

方法 DoSomeWork 在另一个线程上开始一些工作并返回执行ID（只是随机字符串）。稍后，我可以通过返回的执行ID查询结果。重点是要在作业完成前提供执行ID。

Method DoSomeWork starts some work on another thread and returns execution ID (just random string). Later on I can query results by the returned execution ID. Main point is to make execution ID available before job will complete.

现在，我想更改签名以返回 Task ，因此用户可以根据需要等待。

Now I want to change signature to return Task, so user can wait if he want to.

Task DoSomeWork();

同时，我仍然需要返回执行ID（例如，用于跟踪），我看到了一些选择。首先，使用 out 参数，其次，返回具有执行ID和任务的元组（在C＃中，这似乎不是最佳选择），其三，我实际上想要的

At the same time I still need to return execution ID (for tracing purposes for example) and I see a few options. First, use an out parameter, second, return tuple with both execution ID and task (in C# this looks like not a best option), and third, about which I actually want to ask.

如果我创建一个派生 Task 的类怎么办：

What if I create a class that derives Task:

public class ExtendedTask : Task
{
     public string ExecutionID {get; set;}
}

这看起来还好吗？还是决定其他选择更好？

Does this look ok? Or is it better to decide other options?

P.S。在BCL中，有些类是从 Task 派生的。

P.S. In BCL there are some classes derived from Task.

UPDATE ，看来我是无法对此进行足够清晰的定义。但是我需要在作业完成之前访问ExecutionID，所以我不能使用 Task.Result 。

UPDATE, seems I was not able to define this clear enough. But I need access to ExecutionID before the job completes so I cannot use Task.Result.

推荐答案

我个人不会扩展 任务< T> ，而是撰写 。这样一来，您无需担心任何仅返回 Task< T> 的API-您只需包装任务即可。您可以拥有一个公开基础任务的属性，出于C＃5异步的目的，您可以在自己的类型上实现waiter模式-但在我看来，创建自己的派生类型是可能弊大于利。

I wouldn't personally extend Task<T>, I'd compose it instead. That way you don't need to worry about any APIs which only return Task<T> - you can just wrap the task. You can have a property which exposes the underlying task, and for the C# 5 async purposes you can implement the awaiter pattern on your own type - but it feels to me like creating your own derived type is likely to do more harm than good. It's mostly a gut feeling though.

另一种选择是反过来工作：将您的额外状态存储在 Task.AsyncState 属性；毕竟这就是它的目的。这样一来，您就可以轻松地传递任务，而不会丢失逻辑上属于逻辑部分的执行上下文。

Another option is to work the other way round: store your extra state in the Task.AsyncState property; that's what it's there for, after all. That way you can easily pass the task around without losing the execution context it's logically part of.

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