function CustomerSelectedChanged() {

                var comboBox = <%= cmbLookUp.ClientID %>;

                var CustomerCode = comboBox.GetValue();

                //document.getElementById("<%=txtFrom.ClientID %>").value = 'manik';

                  <%=rdCallBackCustDetails.ClientID%>.MakeCallback('GetCustomerDetails',CustomerCode);

            }

' this is code behind

Private Sub RadCallback1_Callback(ByVal sender As System.Object, ByVal args As Telerik.WebControls.CallbackEventArgs) Handles rdCallBackCustDetails.Callback

        If args.CallbackEvent = "GetCustomerDetails" And args.Args <> "" Then

            Try

                MakeControlsUpdatable()

                Dim CustomerData As New FreightComDN.cls_Customer(ConfigurationManager.AppSettings("FreightConStr"))

                Dim resultcol As Collection

                Dim CustomerCode As String

                CustomerCode = args.Args

                resultcol = CustomerData.getASpecificCustomer(args.Args)

                SetText(Me.txtFrom, resultcol.Item(1).customerName)

                CustomerData = Nothing

            Catch ex As Exception

            End Try

            End If

        End If

    End Sub

Private Function MakeControlsUpdatable()

        Try

            ' set all the controls to be updated

            rdCallBackCustDetails.ControlsToUpdate.Add(Me.txtFrom)

        Catch ex As Exception

        End Try

    End Function

Private Sub SetText(ByVal txtBox As TextBox, ByVal txtValue As Object)

        Try

            txtBox.Text = txtValue

        Catch ex As Exception

        End Try

    End Sub

Hello,

I have an ASP.NET page that contains a standard asp:Label at the top of the page in order to display a page title. Below the page title, there are 2 RadGrid controls. The first grid displays parent records that are stored in a database. When an item is selected in the first grid, the second grid is then populated with child records (stored in the same database). This all works fine.

Because there is a 2 - 3 second wait after selecting an item in the first grid and the time it takes to populate the second grid, I have added a RadAjaxLoadingPanel to my ASP.NET page. This is the first time that I have used a LoadingPanel, so I have followed a Telerik demo as a guide for configuring the LoadingPanel.

When I now open my ASP.NET page and click on an item in the first grid, the LoadingPanel appears for about 3 seconds, and then everything on the page disappears, except for the title at the top of the page. Both grids are gone; neither of them are visible on the page. What would cause this to happen? I have double and triple-checked the settings of my LoadingPanel, comparing them to the settings shown in the Telerik demo (http://demos.telerik.com/aspnet-ajax/ajax/examples/loadingpanel/loadingimages/defaultcs.aspx). I have also googled this issue for help, but I cannot determine what I am missing.

Has anyone seen a problem like this and how do I resolve the problem?

Thank you,
Steven