欲在多个流动需要以进行处理（每个流）队列相关任务。该流可以被并行处理。

I want to queue dependant tasks across several flows that need to be processed in order (in each flow). The flows can be processed in parallel.

要具体，让我们说，我需要两个队列，我想每个队列的任务​​，以便进行处理。下面是示例伪code来说明所期望的行为：

To be specific, let's say I need two queues and I want the tasks in each queue to be processed in order. Here is sample pseudocode to illustrate the desired behavior:

Queue1_WorkItem wi1a=...;

enqueue wi1a;

... time passes ...

Queue1_WorkItem wi1b=...;

enqueue wi1b; // This must be processed after processing of item wi1a is complete

... time passes ...

Queue2_WorkItem wi2a=...;

enqueue wi2a; // This can be processed concurrently with the wi1a/wi1b

... time passes ...

Queue1_WorkItem wi1c=...;

enqueue wi1c; // This must be processed after processing of item wi1b is complete

下面是用箭头表示工作项之间的依赖关系图：

Here is a diagram with arrows illustrating dependencies between work items:

现在的问题是我怎么这个用C＃4.0 /做.NET 4.0？现在我有两个工作线程，每个队列之一，我用 BlockingCollection＆LT;＆GT; 为每个队列。我想，而不是使用.NET线程池，并有工作线程处理项目同时（在整个流），但在连续的流动。换句话说，我希望能够指示例如wi1b取决于wi1a完成，而不必跟踪完成并记住wi1a，当wi1b到达。换句话说，我只想说，我想提出一个工作项队列1，这是与我已经提交了队列1，但可能与提交给其他队列工作项目并联等物品串行处理。

The question is how do I do this using C# 4.0/.NET 4.0? Right now I have two worker threads, one per queue and I use a BlockingCollection<> for each queue. I would like to instead leverage the .NET thread pool and have worker threads process items concurrently (across flows), but serially within a flow. In other words I would like to be able to indicate that for example wi1b depends on completion of wi1a, without having to track completion and remember wi1a, when wi1b arrives. In other words, I just want to say, "I want to submit a work item for queue1, which is to be processed serially with other items I have already submitted for queue1, but possibly in parallel with work items submitted to other queues".

我希望这说明是有意义的。如果没有，请随时提问的意见，我会相应地更新这个问题。

I hope this description made sense. If not please feel free to ask questions in the comments and I will update this question accordingly.

感谢您的阅读。

更新：

要总结硬伤的解决方案，到目前为止，这里有来自答案部分，我不能使用的解决方案和原因（S）我为什么不能使用它们：

To summarize "flawed" solutions so far, here are the solutions from the answers section that I cannot use and the reason(s) why I cannot use them:

TPL任务需要指定先行任务的 ContinueWith（）。我不希望提交一个新的任务时，保持每个队列的前提任务的知识。

TPL tasks require specifying the antecedent task for a ContinueWith(). I do not want to maintain knowledge of each queue's antecedent task when submitting a new task.

TDF ActionBlocks看起来很有希望，但它会出现贴到ActionBlock项目并行处理。我需要的物品的特定队列进行串行处理。

TDF ActionBlocks looked promising, but it would appear that items posted to an ActionBlock are processed in parallel. I need for the items for a particular queue to be processed serially.

更新2：

RE：ActionBlocks

RE: ActionBlocks

这样看来，设置 MaxDegreeOfParallelism 选项之一prevents提交给一个 ActionBlock 。因此，它似乎有一个 ActionBlock 每个队列解决了我的问题，唯一的缺点是，这需要从微软的TDF库的安装和部署，我是希望有一个纯粹的.NET 4.0的解决方案。到目前为止，这是考生公认的答案，除非有人能想出办法用纯.NET 4.0的解决方案，不变质为每个队列工作线程（这我已经使用）做到这一点。