Re: Delegate.BeginInvoke and EndInvoke.

Thanks for your response.

Do you know if the AsyncCallback would get called if it times out? If
so, then I could pass the delegate down to the callback and call
EndInvoke.

Every example of timing out a method, using BeginInvoke and EndInvoke,
doesn't make a call to EndInvoke in the timed-out case.

see:
http://www.ondotnet.com/pub/a/dotnet/2003/02/24/asyncdelegates.html
http://www.eggheadcafe.com/tutorials/aspnet/847c94bf-4b8d-4a66-9ae5-5b61
f049019f/basics-make-any-method-c.aspx


-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps
and controls [mailto:[email protected]] On Behalf Of
Peter Ritchie
Sent: Tuesday, January 15, 2008 11:08 AM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] Delegate.BeginInvoke and EndInvoke.

The only EndInvoke that I know of where you're not "required" to call it
is Control.EndInvoke.

See the comments in
http://blogs.msdn.com/cbrumme/archive/2003/05/06/51385.aspx

There are various object that are kept around until EndInvoke is called,
depending on the delegate this may include return value, exception(s),
state, etc.

In your timed-out case, you'll force the thread to block until the
delegate has completed running, which probably defeats the purpose of
timing-out.

You could spawn another thread that waits on the AsyncWaitHandle and
simply calls EndInvoke when it becomes signaled.  That way you free your
current thread to time-out and the EndInvoke is handled in the
background.  It could very well be there's an example of this
somewhere...

On Tue, 15 Jan 2008 10:17:09 -0700, Bhatnagar, Amit
<[email protected]> wrote:

>I have made a service to timeout a method call by launching a delegate 
>asynchronously via BeginInvoke. The documentation states, indirectly, 
>that the call to BeginInvoke should be followed by a call to EndInvoke 
>to prevent leaks. However, I am not sure if the call to EndInvoke is 
>required should the delegate timeout because the call to EndInvoke will

>block the thread and wait for the delegate to complete. So I think what

>I have is OK, but can anyone confirm if the call to EndInvoke is 
>required if it timesout?
>
>See the following code:
>
>---
>IAsyncResult asyncResult = d.BeginInvoke(null, new object());
>
>if (asyncResult.AsyncWaitHandle.WaitOne(7000, true)) {
>   // Not timed out...
>   d.EndInvoke(asyncResult);
>}
>
>else
>{
>   //Timed out ... EndInvoke required here?
>}
>

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