Task Dataflow, can a data block be changed from completion state?

Question

I would like to know whether it is possible to change the completion state of data blocks?

For example, I marked a var block = new BufferBlock();

Answer 1

No, you can't “uncomplete” a completed dataflow block. I think what you should do is to add a flag to each message that says whether it's last message in a run. To make it simpler to work with it, you could create set of helper methods like:

public static TransformBlock<Tuple<TInput, bool>, Tuple<TOutput, bool>>
    CreateEnhancedTransformBlock<TInput, TOutput>(Func<TInput, TOutput> transform)
{
    return new TransformBlock<Tuple<TInput, bool>, Tuple<TOutput, bool>>(
        tuple => Tuple.Create(transform(tuple.Item1), tuple.Item2));
}

This way, you enter a transform delegate that deals just with TInput and TOuput and the flag is transfered along with each message.