如果PostDataflowBlockOptions.BoundedCapacity不是默认值，是否避免使用ActionBlock< TInput> .Post？

本文介绍了如果PostDataflowBlockOptions.BoundedCapacity不是默认值，是否避免使用ActionBlock&lt; TInput&gt; .Post？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我听说如果您使用 Post 方法而不是 SendAsync 方法会丢失信息。 ActionBlock< T> 对象，当您决定使用它的 BoundedCapacity 属性时。I've heard that you can lose information if you use the Post method instead of the SendAsync method of an ActionBlock<T> object, when you decide to utilize it's BoundedCapacity property.有人可以解释为什么会这样吗？Could someone please explain why that is so?推荐答案 Post 方法尝试同步发布项目，并返回 true 或 false ，具体取决于块是否接受了该项目或不。不接受项目的原因：The Post method attempts to post an item synchronously and returns true or false, depending on whether the block accepted the item or not. Reasons to not accept an item: 将该区块标记为已完成（通过调用其 Complete 方法）。 该块已成功完成或未成功完成（其 Completion.IsCompleted 属性返回 true ）。 该块具有有限的容量（选项 BoundedCapacity！= -1 ），并且其缓冲区当前已满。 The block is marked as completed (by calling its Complete method).The block is completed, either successfully or unsuccessfully (its Completion.IsCompleted property returns true).The block has a bounded capacity (option BoundedCapacity != -1), and its buffer is currently full. SendAsync 方法尝试异步发布项目并返回任务< bool> 。除非块具有有限的容量，其缓冲区当前已满并且当前尚未完成或标记为已完成，否则该任务将始终完成。这是 SendAsync 唯一会异步表现的情况。等待任务后，任务的 bool 结果指示该块是否接受了该项目。不接受项目的原因：The SendAsync method attempts to post an item asynchronously and returns a Task<bool>. This task will always be completed, unless the block has a bounded capacity, its buffer is currently full, and it's not currently completed or marked as completed. This is the only case that the SendAsync will behave asynchronously. After awaiting the task, the bool result of the task indicates whether the block accepted the item or not. Reasons to not accept an item: 在调用 SendAsync ，或者在等待期间。 该块在调用 SendAsync 之前完成，或者在等待期间完成或因为其 The block was marked as completed either before calling the SendAsync, or during the awaiting.The block was completed either before calling the SendAsync, or during the awaiting as a result of an exception, or because its Fault method was invoked.因此调用了code> Fault 方法。 c $ c> Post 和 SendAsync 是重点（3）。在具有完整缓冲区的有限容量块的情况下，它们的行为有所不同。在这种情况下， Post 立即拒绝该项目，而 SendAsync 将在缓冲区再次具有可用空间时异步接受该项目。 So the difference between Post and SendAsync is the point (3). They behave differently in the case of a bounded-capacity block with a full buffer. In this case the Post rejects immediately the item, while the SendAsync will asynchronously accept it when the buffer has free space again.在大多数情况下， SendAsync 的行为是可取的。使用 Post 代替 SendAsync 可以看作是一个等待发生的错误，一段时间后，将block重新配置为有界，以解决新发现的与过度使用内存有关的问题。In most cases the behavior of SendAsync is the desirable one. Using the Post instead of the SendAsync can be seen as a bug that is waiting to happen, when some time later the block is reconfigured as bounded, to solve newly discovered problems related with excessive memory usage.不放弃这两种方法的返回值是一个好主意，因为返回 false 的值在大多数情况下表示错误。很少有人会想到并准备处理 false 结果。一些想法：It is a good idea to not dismiss the return value of both methods, because a return value of false indicates in most cases a bug. it is quite rare to expect and be ready to handle a false result. Some ideas:if (!block.Post(item)) throw new InvalidOperationException();if (!await block.SendAsync(item)) throw new InvalidOperationException();var accepted = block.Post(item); Debug.Assert(accepted);var accepted = await block.SendAsync(item); Debug.Assert(accepted); 这篇关于如果PostDataflowBlockOptions.BoundedCapacity不是默认值，是否避免使用ActionBlock&lt; TInput&gt; .Post？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！