Question

我有一个BufferBlock链接到两个目标块。数据流未完成。我遵循了this post的建议，但我无法完成正确的传播。

任何帮助都将不胜感激。

// define blocks
var bufferBlock = new BufferBlock<int>(); 

var actionBlock1 = new TransformBlock<int, int>(i =>
{
    Console.WriteLine($"actionBlock1: {i}");
    return i;
});
var actionBlock2 = new ActionBlock<int>(i =>
{
    Console.WriteLine($"actionBlock2: {i}");
});

// link blocks 
bufferBlock.LinkTo(actionBlock1, i => i == 1);
bufferBlock.LinkTo(actionBlock2, i => i == 2);
bufferBlock.LinkTo(DataflowBlock.NullTarget<int>()); 

// push to block 
var items = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
foreach (var i in items)
{
    bufferBlock.Post(i);
}

// wait for all operations to complete
bufferBlock.Complete();

// NB: block will only propagate completion to one block regardless of how many blocks are linked. This even applies to the BroadcastBlock that broadcasts messages, it will not broadcast completion. In that case you can configure a continuation on the Completion Task
// see https://stackoverflow.com/questions/47310402/tpl-complete-vs-completion/47311537#47311537
var bufferBlockCompletion = bufferBlock.Completion.ContinueWith(tsk =>
{
    if (!tsk.IsFaulted)
    {
        actionBlock1.Complete();
        actionBlock2.Complete();
    }
    else
    {
        ((IDataflowBlock)actionBlock1).Fault(tsk.Exception);
        ((IDataflowBlock)actionBlock2).Fault(tsk.Exception);
    }
});

await Task.WhenAll(bufferBlockCompletion, actionBlock1.Completion, actionBlock2.Completion);

Answer 1

actonBlock1是TransformBlock，与任何内容都没有关联。块生成的任何项目都将保留在其输出缓冲区中，此cas中仅包含数字1.当项目卡在输出中时，块永远无法完成。您可以根据自己的需要确定几种不同的方法。

1）将TransformBlock更改为ActionBlock

2）将TransformBlock链接到NullTarget或其他区块。

TPL数据流未完成多个目标

1 个答案: