WriteOnceBlock<T>.ISourceBlock<T>.ConsumeMessage Method

Definition

Namespace:

System.Threading.Tasks.Dataflow

Assembly:

System.Threading.Tasks.Dataflow.dll

Source:

WriteOnceBlock.cs

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

 virtual T System.Threading.Tasks.Dataflow.ISourceBlock<T>.ConsumeMessage(System::Threading::Tasks::Dataflow::DataflowMessageHeader messageHeader, System::Threading::Tasks::Dataflow::ITargetBlock<T> ^ target, [Runtime::InteropServices::Out] bool % messageConsumed) = System::Threading::Tasks::Dataflow::ISourceBlock<T>::ConsumeMessage;

T ISourceBlock<T>.ConsumeMessage (System.Threading.Tasks.Dataflow.DataflowMessageHeader messageHeader, System.Threading.Tasks.Dataflow.ITargetBlock<T> target, out bool messageConsumed);

abstract member System.Threading.Tasks.Dataflow.ISourceBlock<T>.ConsumeMessage : System.Threading.Tasks.Dataflow.DataflowMessageHeader * System.Threading.Tasks.Dataflow.ITargetBlock<'T> * bool -> 'T
override this.System.Threading.Tasks.Dataflow.ISourceBlock<T>.ConsumeMessage : System.Threading.Tasks.Dataflow.DataflowMessageHeader * System.Threading.Tasks.Dataflow.ITargetBlock<'T> * bool -> 'T

Function ConsumeMessage (messageHeader As DataflowMessageHeader, target As ITargetBlock(Of T), ByRef messageConsumed As Boolean) As T Implements ISourceBlock(Of T).ConsumeMessage

Parameters

messageHeader

DataflowMessageHeader

The DataflowMessageHeader of the message being consumed.

target

ITargetBlock<T>

The ITargetBlock<TInput> consuming the message.

messageConsumed

Boolean

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

Returns

T

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(DataflowMessageHeader, ITargetBlock<TOutput>, Boolean). The consuming ITargetBlock<TInput> must use the returned value instead of the value passed as messageValue through OfferMessage(DataflowMessageHeader, TInput, ISourceBlock<TInput>, Boolean).

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

Implements

ConsumeMessage(DataflowMessageHeader, ITargetBlock<TOutput>, Boolean)

Exceptions

ArgumentException

The messageHeader is not valid.

ArgumentNullException

The target is null.

Remarks

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.