Load On Demand - Unable To Get Value Error

[Aash]

Im getting the attached error with a radcombobox set up as descrubed below:

<telerik:RadComboBox ID="radComboBoxClientName" runat="server" Filter="Contains"
              Width="300px" Height="300" DataTextField="ClientAltName" DataValueField="ClientId"
              AutoPostBack="True" CausesValidation="false" EnableLoadOnDemand="True" EnableVirtualScrolling="true"
              EmptyMessage="No Client Selected" OnClientItemsRequesting="OnKPClientItemsRequesting">
              <WebServiceSettings Method="GetClients" Path="~/Services/AutoCompleteService.svc" />
          </telerik:RadComboBox>

Public Function GetClients(ByVal context As RadComboBoxContext) As RadComboBoxData
    Dim result As RadComboBoxData = New RadComboBoxData()
    Dim allClients As List(Of RadComboBoxItemData)

    Dim contextDictionary As IDictionary(Of String, Object) = DirectCast(context, IDictionary(Of String, Object))
    Dim deptCode As String = (DirectCast(contextDictionary("DeptCode"), String))
    Dim display As String = (DirectCast(contextDictionary("Display"), String))


    'Select Case deptCode
    'Case "EFF"
    '   From cli As Client In ClientCache.GetCacheDataTypedList
    '                  Where cli.IsValidETFMS
    '                  Select New RadComboBoxItemData With {.Text = If(display = "Short", cli.ClientShortAltName, cli.ClientAltName), .Value = CStr(cli.ClientId)}).OrderBy(Function(c) c.Text).ToList
    'Case Else
    '    allClients = (From cli As Client In ClientCache.GetCacheDataTypedList
    '                  Select New RadComboBoxItemData With {.Text = If(display = "Short", cli.ClientShortAltName, cli.ClientAltName), .Value = CStr(cli.ClientId)}).OrderBy(Function(c) c.Text).ToList

    'TODO : Dont like using SP, AAP.
    Dim qnClients As New List(Of DataLayer.qn_Client_getResult)
    Using kp As New DataLayer.KestrelProLinq.KestrelProDb
        qnClients = kp.qn_Client_get(deptCode).ToList()
    End Using
    allClients = (From cli As DataLayer.qn_Client_getResult In qnClients
                  Select New RadComboBoxItemData With {.Text = If(display = "Short", ClientCache.GetStoreObject.GetClientShortAltName(cli.ShortName, cli.AgressoClientId), ClientCache.GetStoreObject.GetClientAltName(cli.ShortName, cli.Name, cli.AgressoClientId)), .Value = CStr(cli.ClientId)}).OrderBy(Function(c) c.Text).ToList
    'End Select


    Dim text As String = context.Text
    If Not String.IsNullOrEmpty(text) Then
        allClients = (From item As RadComboBoxItemData In allClients
                      Where item.Text.ToLower.Contains(text.ToLower)
                      Select item).ToList
        If allClients.Count <= 1 Then allClients.Add(New RadComboBoxItemData With {.Text = "", .Value = ""})
    End If

    Dim numberOfItems As Integer = context.NumberOfItems
    Dim clients As List(Of RadComboBoxItemData) = allClients.Skip(numberOfItems).Take(100).ToList

    result.Items = clients.ToArray

    Dim endOffSet As Integer = numberOfItems + clients.Count
    Dim totalCount As Integer = allClients.Count

    If endOffSet = totalCount Then result.EndOfItems = True

    'If clients.Count <= 0 Then result.Message = "No Matches"

    Return result
End Function

[Dimitar Terziev]

Hi Aash,

This problem might occur if your web service method returns an empty RadComboBoxData. If this is the case then you should try to stop the compression for the page with the RadComboBox using the following approach:

[Telerik.Web.UI.RadCompressionSettings(HttpCompression = Telerik.Web.UI.CompressionType.None)]
public partial class Default_Cs : System.Web.UI.Page
{
    ...
}

All the best,
Dimitar Terziev
the Telerik team