Synchronous and Asynchronous Callbacks

Question

I am confused with some terms when reading MSDN documents and code samples.

What are callbacks in C #? In particular, what are synchronous and asynchronous callbacks?

Please explain this from a layman's point of view.

Also explain the IAsyncCallback interface IAsyncResult. How can we do this? (with a very simple example)

Thanks in advance.

Answer 1

The interface IAsyncCallbackdoes not exist, so you cannot implement it.

I suspect you really want to know about the IAsyncResultinterface .

MSDN.

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IAsyncResult interface (, - ), , . , ( IsCompleted). WaitHandle ( AsyncWaitHandle), . ( result.AsyncWaitHandle.WaitOne())

IAsyncResult, Begin Whatever. (BeginExecuteReader, BeginGetResponse ). Begin Whatever , (, BeginExecuteReader CommandBehavior), AsyncCallback ( ) . IAsyncResult.

AsyncCallback - , , , . , . AsyncCallback IAsyncResult, Begin Whatever . IAsyncResult ; AsyncCallback, , . ( , , null)

AsyncCallback ( - ) End Whatever, Begin Whatever, . IAsyncResult Begin Whatever AsyncCallback. , ( ), . (, -, , WebRequest.EndGetResponse WebResponse). , End Whatever .

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IAsyncResult, , . Begin Whatever End Whatever, . IAsyncResult . .

Answer 2

( ) , , , - .

( ) - , .

, , "", - , .

Answer 3

- , . , () ( ) .

- . , , ( ). Async ( )

IAsyncCallback . (), , . , .