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TransformManyBlock<TInput, TOutput>::ISourceBlock<TOutput>::ConsumeMessage Method (DataflowMessageHeader, ITargetBlock<TOutput>^, Boolean)

 

Called by a linked ITargetBlock<TInput> to accept and consume a DataflowMessageHeader previously offered by this ISourceBlock<TOutput>.

Namespace:   System.Threading.Tasks.Dataflow
Assembly:  System.Threading.Tasks.Dataflow (in System.Threading.Tasks.Dataflow.dll)

private:
virtual TOutput ConsumeMessage(
	DataflowMessageHeader messageHeader,
	ITargetBlock<TOutput>^ target,
	[OutAttribute] bool% messageConsumed
) sealed = ISourceBlock<TOutput>::ConsumeMessage

Parameters

messageHeader
Type: System.Threading.Tasks.Dataflow::DataflowMessageHeader

The DataflowMessageHeader of the message being consumed.

target
Type: System.Threading.Tasks.Dataflow::ITargetBlock<TOutput>^

The ITargetBlock<TInput> consuming the message.

messageConsumed
Type: System::Boolean

true if the message was successfully consumed; otherwise, false.

Return Value

Type: TOutput

The value of the consumed message. This may correspond to a different DataflowMessageHeader instance than was previously reserved and passed as the messageHeader to ConsumeMessage. The consuming ITargetBlock<TInput> must use the returned value instead of the value passed as messageValue through OfferMessage ITargetBlock<TInput>::OfferMessage

If the message requested is not available, the return value will be null.

Exception Condition
ArgumentException

The messageHeader is not valid.

ArgumentNullException

The target is null.

Only ITargetBlock<TInput> instances linked to this ISourceBlock<TOutput> instance may use ConsumeMessage, and it must only be used to consume DataflowMessageHeader instances previously offered by this source to the target.

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