Cascading DropDown not working in or out of UpdatePanel

Hello,

I am trying to do something really simple.  I am trying to capture the SelectedIndexChanged event in one dropdown, use the value as a parameter to fire a stored procedure - and then populate a second drop down with the values.

It doesnt work.  When I step through the code, I see that the DataReader is returning records, and appears to be going through the process of adding items to the drop down..only the original entry from the inital page load is in the drop down in the browser.

I have eveything in an UpdatePanel, but it doesnt work in or out of the UpdatePanel.  I have reverted to the DataReader.Read method as a last resort....because the DataBind method wasnt working either.

Surely this is bread and butter stuff!?

Regards

p_love





    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        ' First we need to populate the drop down lists
        If Not Page.IsPostBack And Not Me.ScriptManager1.IsInAsyncPostBack Then
            Call Bind_Filters()
        End If

    End Sub




    Private Sub Bind_Filters()
        ' Bind all the filters
        Call Bind_DropDown("SP_DUNDAS_LUT_01", Me.ddSubstance, "Substance", False, "@TA", "Oncology/Infection")
        Call Bind_DropDown("SP_DUNDAS_LUT_02", Me.ddProject, "Project", True, "@SUBSTANCE", "(All)")
        Call Bind_DropDown("SP_DUNDAS_LUT_03", Me.ddActivity, "Activity", True, "@PROJECT", "(All)")
        Call Bind_DropDown("SP_DUNDAS_LUT_04", Me.ddRegion, "Region", False)
        Call Bind_DropDown("SP_DUNDAS_LUT_05", Me.ddSite, "Site", True, "@REGION", "(All)")


    End Sub


    Private Sub Bind_DropDown(ByVal strCommand As String, ByVal dd As DropDownList, ByVal strDataTextField As String, ByVal blnInitialise As Boolean, Optional ByVal strParamName As String = Nothing, Optional ByVal strParam As String = Nothing)

        Dim request As New MISF.MISFDataRequest
        Dim param As New MISF.MISFDataRequest.DataParameter
        Dim factory As MISF.MISFDataAbstractFactory
        Dim ds As MISF.MISFDataSet
        Dim dsFinal As New DataSet
        Dim dr As IDataReader


        If blnInitialise = False Then
            factory = New MISF.MISFSqlFactory

            With request
                .Command = strCommand
                .CommandType = CommandType.StoredProcedure

                If Not (strParam Is Nothing) And Not (strParamName Is Nothing) Then
                    ' We only need to add parameters to the collection if we have any!
                    param.ParamName = strParamName
                    param.ParamValue = strParam

                    .Parameters.Add(param)
                End If

                .Role = MISF.MISFDataRequest.UserRole.Writer

                .Transactional = False

            End With

            ds = factory.ExecuteDataSet(request)

            dsFinal = ds.ReturnedDataSet

            dd.Items.Clear()

            dr = dsFinal.Tables(0).CreateDataReader

            While dr.Read
                dd.Items.Add(dr.Item(0))
            End While



        ElseIf blnInitialise = True Then
            ' This is a first pass initialisation and so we only need to add "(All)"
            dd.Items.Add("(All)")
        End If

        Page.DataBind()

    End Sub





    Protected Sub ddSubstance_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddSubstance.SelectedIndexChanged
        Dim strValue As String

        If ScriptManager1.IsInAsyncPostBack Then
            strValue = ddSubstance.SelectedItem.Value
            If strValue = "(All)" Then
                Call Bind_DropDown("SP_DUNDAS_LUT_02", Me.ddProject, "Project", True)
                Call Bind_DropDown("SP_DUNDAS_LUT_03", Me.ddActivity, "Activity", True)
            Else
                Call Bind_DropDown("SP_DUNDAS_LUT_02", Me.ddProject, "Project", False, "@SUBSTANCE", strValue)
                Call Bind_DropDown("SP_DUNDAS_LUT_03", Me.ddActivity, "Activity", False, "@PROJECT", ddProject.SelectedItem.Value)

            End If
        End If


    End Sub