asynchronous programming in .net

[Guest]

Does anyone know a good tutorial on asynchronous programming in .net

AsyncCallback And IASyncResult are driving me crazy. And the msdn documentation is not really helpful on this topic

I appreciate any recommendation.

 

[Cor]

Hi Anonymous

Have a look for "remoting" on msdn, I think the first week you have enough
to do reading about async.

You can also download the vb. resource kit there are samples in it.

http://msdn.microsoft.com/vbasic/vbrkit/default.aspx

And if you have problems installing it

http://msdn.microsoft.com/vbasic/vbrkit/faq/#installvdir
I hope this helps a little bit?

Cor

Does anyone know a good tutorial on asynchronous programming in .net?

AsyncCallback And IASyncResult are driving me crazy. And the msdn

documentation is not really helpful on this topic.

 

[Paul Kimmel]

If you want VB try Visual Basic .NET Power Coding, for C3
try Advanced C#, or sign up for the VB Today codeguru.com
newsletter. The VB Today columns should have a couple
examples.

The callback is a delegate/function pointer that does the
work, and the IAsyncResult is a waithandle (I think!?) for
blocking.

Paul

-----Original Message-----
Does anyone know a good tutorial on asynchronous programming in .net?

AsyncCallback And IASyncResult are driving me crazy. And

the msdn documentation is not really helpful on this topic.

 

[Trev Hunter]

As Cor mentioned, you could use some of the samples in the Remoting
infrastructure, although multithreading and asynchronous programming don't
have to involve remoting - remoting is more or less the .net version of
DCOM.

Here's some links that may help you out with threads and asynchronous
programming.

http://msdn.microsoft.com/library/d...n-us/vbcn7/html/vaconFreeThreadingExample.asp

http://msdn.microsoft.com/msdnmag/issues/01/07/vbnet/default.aspx

http://msdn.microsoft.com/library/d...dowsformsmultithreadedtciiplistenersample.asp

I suggest you also look up topics relating to the "thread pool" and
asynchronous delegates.

Here's a quick example on how to call a method asynchronously in VB.net with
one parameter (there are more ways to do this, but this is just a simple
example)

-------------------------

' Delegate to call async
Private Delegate Sub DoStuffDelegate(Byval MyParam as String)



' Main Entry point
Private Sub Main()

' Local Variables
Dim DoStuffAsync as new DoStuffDelegate(AddressOf Me.DoStuff)
Dim objResult as IAsyncResult

' Start the async processing
objResult = DoStuffAsync.BeginInvoke(nothing, nothing)

' Do some stuff in this thread
Threading.Thread.Sleep(5000)

' Pause until the processing has finished
DoStuffAsync.EndInvoke(objResult)

End Sub


' Method that runs on a different thread
Private Sub DoStuff()

' Do stuff on a different thread
Threading.Thread.Sleep(10000)

End Sub

-------------------------

HTH,

Trev.

Does anyone know a good tutorial on asynchronous programming in .net?

AsyncCallback And IASyncResult are driving me crazy. And the msdn

documentation is not really helpful on this topic.

 

[Guest]

Ok, but, doesnt a normal delegate doesnt do the work in the same manner as a AsyncCallback delegate? What is the difference? Its not like the asynchronous delegate works indeed asynchronous to the parent program

----- Paul Kimmel wrote: ----
The callback is a delegate/function pointer that does the
work, and the IAsyncResult is a waithandle (I think!?) for
blocking

Pau

 

[Trev Hunter]

Sorry. Bug Fix.... (forgot the parameter!)

-------------------------

' Delegate to call async
Private Delegate Sub DoStuffDelegate(Byval MyParam as String)



' Main Entry point
Private Sub Main()

' Local Variables
Dim DoStuffAsync as new DoStuffDelegate(AddressOf Me.DoStuff)
Dim objResult as IAsyncResult

' Start the async processing
objResult = DoStuffAsync.BeginInvoke("test", nothing, nothing)

' Do some stuff in this thread
Threading.Thread.Sleep(5000)

' Pause until the processing has finished
DoStuffAsync.EndInvoke(objResult)

End Sub


' Method that runs on a different thread
Private Sub DoStuff(Byval Param as String)

' Do stuff on a different thread
Threading.Thread.Sleep(10000)

End Sub

 

[Michael Bray]

To be honest.. not really. My problem is, i dont see the advantage of
the AsyncCallback delegate over a normal delegate.. What is the
advantage? The only advantage that i can see, is the IAsyncResult
object, that has useful members.

Maybe i dont got it, can someone explain it to me? Asynchronous over
synchronous.

Just because a delegate is a delegate doesn't mean that it runs
asynchronously. Normal delegates have to complete their processing before
the call to invoke the delegate will return.

-mdb