C# - Using Delegate Function

[microkarl]

All, I am a VB.NET programmer so please excuse me if the question is kinda dumb. I have a Web Service and a web page to call and retrieve data from the web serivce and pop them into a datagrid, the code is as follow:

 

 
   Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


       Dim objWS As New NorthWindWS.Products
       Try
           If Not Page.IsPostBack Then
               objWS.BeginRetrieveAllProducts(New AsyncCallback(AddressOf RetrieveData_CallBack), objWS)
           Else
               lblError.Visible = False
               lblError.Text = String.Empty
           End If
       Catch ex As Exception
           lblError.Visible = True
           lblError.Text = ex.ToString
       End Try
   End Sub

   Private Sub RetrieveData_CallBack(ByVal ar As System.IAsyncResult)

       Dim dsTemp As New DataSet
       Dim ws As NorthWindWS.Products = CType(ar.AsyncState, NorthWindWS.Products)
       dsTemp = ws.EndRetrieveAllProducts(ar)

       With dgProducts
           .DataSource = dsTemp.Tables(0)
           .DataBind()
       End With

   End Sub

End Class

 

If I have to do the exact same thing in C#, how to do it? I know C# is more strict on using delegates and need to declare the delegate functions first before using... can anyone help!

 

Thanks,

Carl

[PlausiblyDamp]

Something like

       private void Page_Load(object sender, EventArgs e)
       {

           NorthWindWS.Products objWS = new NorthWindWS.Products();
           try
           {
               if (!Page.IsPostBack)
                   objWS.BeginRetrieveAllProducts(new AsyncCallback(RetrieveData_CallBack), objWS);
               else
               {
                   lblError.Visible = False;
                   lblError.Text = String.Empty;
               }
           }
           catch (Exception exception)
           {
               lblError.Visible = true;
               lblError.Text = ex.ToString();
           }

       }

       private void RetrieveData_CallBack(IAsyncResult ar)
       {
           DataSet dsTemp = new DataSet();
           NorthWindWS.Products ws = (NorthWindWS.Products)ar.AsyncState;
           dsTemp = ws.EndRetrieveAllProducts(ar);

           dgProducts.DataSource = dsTemp.Tables(0);
           dgProducts.DataBind();
       }

should do the trick.

[Gill Bates]

You must also include Async="true" in your Page directive:

 

<%@ Page Async="true" Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

[microkarl]

How come when I put the Async="true" in the aspx page. it gave me a run-time error?