Well, According to
http://msdn.microsoft.com/library/de...gmessaging.asp
<quoute>
System.Runtime.Remoting.Messaging namespace are the AsyncResult class....
The AsyncResult class stores and returns the results of an asynchronous
method call. AsyncResult instances contain the return value, call status, the
delegate used for the call, and the other information about the asynchronous
method call.
</quoute>
It's just strange that they put in Remoting.Messaging namespace .
So now, if anyone has advanced knowledge about async callbacks, can someone
expalin why example from a book wont work while msdn.
To summarazie the difference is 1 line of code:
MSDN Working code:
AsyncProcess.AsynExecuteDelegate del =
(AsyncProcess.AsynExecuteDelegate)((AsyncResult)ar ).AsyncDelegate;
Book's Not working code:
AsyncProcess.AsynExecuteDelegate del =
(AsyncProcess.AsynExecuteDelegate)ar.AsyncState;
I will stop taling to myself now :-)
Thanks
"Lenn" wrote:
[color=blue]
> Hello,
>
> I have the following example of AsyncCallback from a C# book which I wanted
> to implement in my project:
>
> //Class with AsyncDelegate
> public class AsyncProcess
> {
> public AsyncProcess()
> {
>
> }
> public delegate int AsynExecuteDelegate(string command);
>
> public System.IAsyncResult BeginExecute(string command,
> System.AsyncCallback callBack)
> {
> //string temp;
> AsynExecuteDelegate executeDelegate = new
> AsynExecuteDelegate(this.Execute);
> return executeDelegate.BeginInvoke(command, callBack, null);
> }
>
> public int Execute(string command)
> {
> System.Diagnostics.Trace.WriteLine(command);
> //more code
> return 1;
> }
> }
>
> //Client BeginExecute Call and CallBack
> private void button2_Click(object sender, System.EventArgs e)
> {
> AsyncProcess aPr = new AsyncProcess();
> aPr.BeginExecute("Do this", new AsyncCallback(ClientCallBack));
>
> }
> private void ClientCallBack(System.IAsyncResult ar)
> {
> AsyncProcess.AsynExecuteDelegate del =
> (AsyncProcess.AsynExecuteDelegate)ar.AsyncState;
>
> int result = del.EndInvoke(ar);
> MessageBox.Show(result.ToString());
> }
> Unfortunately this callback doesn't work, it behaves in a very strange way;
> when I stepped through the callback, it looked like .EndInvoke would cause
> ClientCallBack to be called again, and 2nd time around when it reached
> .EndInvoke it would simply exit the function without returning any value.
> Very Strange!
>
> However this callback from code sample on MSDN
>
http://msdn.microsoft.com/library/de...mingsample.asp Seems to work:
>
> using System.Runtime.Remoting.Messaging;
> ....
> ....
>
> private void ClientCallBack(System.IAsyncResult ar)
> {
> AsyncProcess.AsynExecuteDelegate del =
> (AsyncProcess.AsynExecuteDelegate)((AsyncResult)ar ).AsyncDelegate;
>
> int result = del.EndInvoke(ar);
> MessageBox.Show(result.ToString());
> }
> Can someone explain why that is. Why is it requiring AsyncDelegate wich is
> part of System.Runtime.Remoting.Messaging namespace, what does Remoting has
> to do with AsyncCallbacks?
>
> Thank you[/color]
