Problem with click on item record of a combobox

[Fabio Cirillo]

guys,

when i start the page web and click on combobox after the load the record into combo, if i click on item record i've this error:

"Unable to get the value of the 'get_Count' null object or undefined"

but the same procedure on another combobox does not generate this error.

the combobox that this error is this:

<telerik:RadComboBox ID="Categoria" Runat="server" DropDownWidth="350px" Height="175px"
EmptyMessage="Seleziona la tua categoria" EnableLoadOnDemand="True"
EnableVirtualScrolling="True" LoadingMessage="Caricamento..."
ShowMoreResultsBox="True" Filter="StartsWith"
MaxHeight="175px" Skin="Sunset" Width="350px" EnableItemCaching="True"
Font-Italic="True" Font-Names="Verdana" AutoPostBack="True" >
<WebServiceSettings Path="WebService.asmx" Method="GetCategoryNames" />
</telerik:RadComboBox>

this is code webservice:

Imports System.Web.Services
Imports System.Collections
Imports System.Collections.Generic
Imports System.Web.Script.Services
Imports System
Imports System.Data
Imports System.Web
Imports System.Data.SqlClient
Imports Telerik.Web.UI
<WebService([Namespace]:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ScriptService()> _
Public Class TryWebService
    Private Const ItemsCategoryPerRequest As Integer = 10
    Private Const ItemsCityPerRequest As Integer = 10
    <WebMethod()> _
    Public Function GetCategoryNames(ByVal context As RadComboBoxContext) As RadComboBoxData
        Dim data As DataTable = Getcategoria(context.Text)

        Dim comboData As New RadComboBoxData()
        Dim itemOffset As Integer = context.NumberOfItems
        Dim endOffset As Integer = Math.Min(itemOffset + ItemsCategoryPerRequest, data.Rows.Count)
        comboData.EndOfItems = endOffset = data.Rows.Count

        Dim result As New List(Of RadComboBoxItemData)(endOffset - itemOffset)

        For i As Integer = itemOffset To endOffset - 1
            Dim itemData As New RadComboBoxItemData()
            itemData.Text = data.Rows(i)("descrizione").ToString()
            itemData.Value = data.Rows(i)("id").ToString()
            result.Add(itemData)
        Next
        REM ottengo il messaggio dei record selezionati
        comboData.Message = GetStatusMessage(endOffset, data.Rows.Count)
        comboData.Items = result.ToArray()
        Return comboData
    End Function

    Private Function GetStatusMessage(ByVal offset As Integer, ByVal total As Integer) As String
        If total <= 0 Then
            Return "Nessun dato"
        End If

        Return [String].Format("Record <b>1</b>-<b>{0}</b> di <b>{1}</b>", offset, total)
    End Function
    Private Function Getcategoria(ByVal text As String) As DataTable
        REM SELECT * FROM Tab_categorie WHERE CONTAINS(descrizione, @text)
        REM per indici full text
        Dim conString = ConfigurationManager.ConnectionStrings("TrycontactString")
        Dim strConnString As String = conString.ConnectionString
        Using scope As New Transactions.TransactionScope
            Using db As New SqlConnection(strConnString)
                db.Open()
                Using sqlcmd As New SqlCommand("select_category", db)
                    sqlcmd.CommandType = CommandType.StoredProcedure
                    sqlcmd.Parameters.AddWithValue("@desc", SqlDbType.VarChar).Value = text
                    Dim adapter As New SqlDataAdapter(sqlcmd)
                    Dim data As New DataTable()
                    adapter.Fill(data)
                    Return data
                End Using
            End Using
            scope.Complete()
        End Using
    End Function

[Hristo Valyavicharski]

Hi Fabio,

Could you specify what is the version of your browser and the version of Telerik assemblies that you are using? Is the RadComboBox placed inside RadGrid or other control? I have tested your code under IE9 and it seems that the issue doesn't exists.

All the best,
Hristo Valyavicharski
the Telerik team

[Fabio Cirillo]

the assembly versione is 201.3.1205.40 and the version browser is IE9 and google chrome last version

[Hristo Valyavicharski]

Hi Fabio,

Your code seems to work correctly on those two browsers, please see the video. For your reference here is the code of the stored procedure:

/****** Object:  StoredProcedure [dbo].[select_category]    Script Date: 2/12/2013 9:49:52 AM ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[select_category]
@desc nvarchar(50)

AS

SELECT top 100 Id, Descrizione
FROM Tab_comuni
WHERE Descrizione LIKE @desc + '%'

It would be very helpful if you can open new support ticket and attach sample project demonstrating the faced issue.

Greetings,
Hristo Valyavicharski
the Telerik team