Aync WebClient

[sandrofurlan]

Hi all,
I'm a newbie about asp.net.

I've a web client that call in async mode one webservice method
The problem is that I don't know how to refresh control text property.

Some code:

Protected Sub ServiceCallback(ByVal ar As IAsyncResult)
Dim client As ServiceClient = ar.AsyncState
Dim e As ServiceEventArgs = client.EndWaitEvent(ar)
If e.Status = 4 Then
Label1.text = "result OK" <----
Else
Label1.text = "result False" <----
End If
' reload callback handler
Dim callBack As New AsyncCallback(AddressOf ServiceCallback)
client.BeginWaitEvent(callBack, client)
End Sub

Protected Sub form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles form1.Load
Dim client As New ServiceClient
Label1.Text = "Open" & client.StartService()
Dim callBack As New AsyncCallback(AddressOf ServiceCallback)
Dim Iar As IAsyncResult = client.BeginWaitEvent(callBack,
client)
End Sub

The problem is that label1.text could not change.

Some idea?
Thanks,

Sandro Furlan

 

[bruce barker]

an asp.net page just builds html and sends it to the browser, its not
connected the simple cycle is

1) start request
2) create page class instance
3) call page events
4) return html
5) end request

you are updating the server control after the web request is completed.
the fix is in formload or prerender add a wait until the async call
completes, then continue the page processing.

-- bruce (sqlwork.com)