Name
AsyncCallback
Synopsis
This delegate type is used as part of
asynchronous operations on delegates in general. As described in
Chapter 16, delegates
can be executed in an asynchronous fashion, using a random thread out of
the system-managed thread pool. Frequently, however, programmers
desire notification of the asynchronously executing delegate’s completion,
and the AsyncCallback
is used to achieve that.
Using an AsyncCallback
is fairly straightforward. At
the asynchronous delegate’s invocation, pass in an instance of
this delegate (referring to a void-returning IAsyncResult
-accepting
method) as part of the BeginInvoke()
call. When the
asynchronously executing delegate has finished execution, the method
on the other end of the AsyncCallback
is invoked,
with an IAsyncResult
object as the sole parameter.
(This IAsyncResult
object contains the output
parameters from the delegate’s call: the return value, along with any
out
or ref
parameters declared as part of the method’s signature.)
public delegate void AsyncCallback(IAsyncResult ar);
Passed To
Multiple types
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