C#TPL数据流-完成不起作用 [英] C# TPL Dataflow - Completion not working

问题描述

此代码永远不会到达最后一行，因为完成不会从saveBlock传播到sendBlock.我在做什么错了?

This code never reaches the last line because the completion doesn't propagate from the saveBlock to the sendBlock. What am I doing wrong?

var readGenerateBlock = new TransformBlock<int, int>(n =>
    {
        Console.WriteLine("Read " + n);
        Thread.Sleep(15);
        return n;
    }); 
var groupingBlock = new BatchBlock<int>(10);
var saveBlock = new TransformManyBlock<int[], int>(n =>
    {
        Console.WriteLine("Saving {0} items [{1}; {2}]", n.Count(), n.First(), n.Last());
        Thread.Sleep(150);
        return n;
    }); 
var sendBlock = new TransformBlock<int, int>(n =>
    {
        Console.WriteLine("Sending {0}", n);
        Thread.Sleep(25);
        return n;
    }, new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 2 }); 

readGenerateBlock.LinkTo(groupingBlock, new DataflowLinkOptions { PropagateCompletion = true });
groupingBlock.LinkTo(saveBlock, new DataflowLinkOptions { PropagateCompletion = true });
saveBlock.LinkTo(sendBlock, new DataflowLinkOptions { PropagateCompletion = true });

Parallel.For(0, 250, i => readGenerateBlock.Post(i));
readGenerateBlock.Complete();

sendBlock.Completion.Wait();
Console.WriteLine("Completed.");

推荐答案

您必须先从数据块中读取数据，然后才能完成数据.由于noöne正在读取saveBlock，因此它将永远不会完成.

You have to read the data out of the block before it will be completed. Since noöne is reading saveBlock, it will never be completed.

如果不需要数据，最简单的解决方案是使用ActionBlock而不是TransformBlock.否则，只要继续读取数据，直到完成该块即可.

If you don't need the data, the easiest solution is to use ActionBlock instead of TransformBlock. Otherwise, just keep reading the data until the block is completed.

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