Server-side (Dynamic) Creation of Treeview inside Combobox inside Toolbar

[Tomas]

Consider:

I am dynamically creating a toolbar that has a RadComboBox button, such that I do the following:

' in the page_load:

If Not m_ThisPage.IsPostBack Then
   Dim btnSearchByTxt As New RadToolBarButton()
   btnSearchByTxt.Text = "SearchFor"
   btnSearchByTxt.Value = "searchfor"
   m_RadToolBar.Items.Add(btnSearchByTxt)

   InstantiateSearch()
   Dim cboSearchItem As RadToolBarItem = m_RadToolBar.FindItemByText("SearchFor")
   Dim cboSearchBox As RadComboBox = CType(cboSearchItem.FindControl("SearchComboBox"), RadComboBox)
   AddHandler cboSearchBox.SelectedIndexChanged, AddressOf cboSearchBox_SelectedIndexChanged

End If

' -------------- snip ----------------

    Private Sub InstantiateSearch()

        Dim searchTemplate As New ComboBoxSearchTemplate
        Dim cboSearchItem As RadToolBarItem = m_RadToolBar.FindItemByText("SearchFor")
        'Dim searchTemplate2 As New TextBoxSearchTemplate()
        'Dim textSearchItem As RadToolBarItem = m_RadToolBar.FindItemByText("SearchFor")
        If TypeOf cboSearchItem Is RadToolBarButton Then
            searchTemplate.InstantiateIn(cboSearchItem)
        End If

        m_RadToolBar.DataBind()

    End Sub

    Private Class ComboBoxSearchTemplate

        Implements ITemplate

        Public Sub InstantiateIn(ByVal container As Control) Implements ITemplate.InstantiateIn

            Dim cboBox1 As New RadComboBox()

            cboBox1.ID = "SearchComboBox"
            cboBox1.DropDownWidth = 460
            cboBox1.Sort = RadComboBoxSort.Ascending
            cboBox1.SortCaseSensitive = False
            'cboBox1.DropDownCssClass = "searchDropDown"
            cboBox1.AllowCustomText = True
            cboBox1.AutoPostBack = True
            cboBox1.EmptyMessage = "Search for..."
            cboBox1.EnableItemCaching = True
            cboBox1.EnableLoadOnDemand = True
            cboBox1.MaxHeight = 320
            cboBox1.MaxLength = 2999
            cboBox1.Width = 250
            cboBox1.ExpandDelay = 2500
            cboBox1.LoadingMessage = "Searching..."
            cboBox1.Attributes.Add("onitemsrequested", "SearchComboBox_ItemsRequested")
            'cboBox1.Attributes.Add("onkeydown", "fire()")
            cboBox1.OnClientKeyPressing = "fire"
            cboBox1.CloseDropDownOnBlur = False
            cboBox1.Text = ""
            cboBox1.Font.Size = 9
            cboBox1.Font.Bold = False
            cboBox1.Font.Name = "Sans-Serif"

            cboBox1.DataTextField = "CMM_DESCRIPTION"
            cboBox1.Items.Add(New RadComboBoxItem(""))

            Dim ctt As ComboBoxTreeTemplate = New ComboBoxTreeTemplate
            ctt.InstantiateIn(cboBox1.Items(0))

            AddHandler cboBox1.DataBinding, AddressOf cboBox1_DataBinding
            AddHandler cboBox1.ItemsRequested, AddressOf cboBox1_ItemsRequested
            cboBox1.DataBind()

            container.Controls.Add(cboBox1)

        End Sub

    End Class

    Private Class ComboBoxTreeTemplate

        Implements ITemplate

        Public Sub InstantiateIn(ByVal container As Control) Implements ITemplate.InstantiateIn

            Dim rtv As RadTreeView = New RadTreeView()

            rtv.ID = "RadTreeView1"
            rtv.Skin = "Telerik"
            rtv.SingleExpandPath = True

            rtv.DataTextField = "CMM_DESCRIPTION"
            rtv.DataValueField = "CMM_ID"
            rtv.DataFieldParentID = "CMM_PARENT_ID"

            Dim sProc As String = "sptMaterialInventory_AddEdit_GetCommodity"
            Dim connection As New SqlConnection(ConfigurationManager.ConnectionStrings("TRACURATEConnectionString").ConnectionString)
            Dim adapter As New SqlDataAdapter(sProc, connection)
            adapter.SelectCommand.CommandType = CommandType.StoredProcedure
            Dim dataTable As New DataTable()
            adapter.Fill(dataTable)
            rtv.DataSource = dataTable
            rtv.DataBind()
            container.Controls.Add(rtv)

        End Sub

    End Class

The idea is that I want to populate the combobox in the toolbar, with a treeview.  First, for some reason, the treeview is flat.  If I use the same stored procedure in a treeview that I create in ASPX, it renders perfectly.  Using the exact same in this dynamic fashion, there are no parents/children.  Just a flat list of all nodes.

Second: the treeview is fine the first rendering of the page.  When an AJAX post-back occurs, I get an error stating that the treeview does not exist.

I am looking for two answers:

1) How do I get the full treeview with parent/children to render?
2) How do I cause the treeview to not disappear after the first AJAX post-back?

I hope that this is enough code for you to understand what I am doing.

Thank you,

Tomas

[Tomas]

I've attached a screen shot of the error that I receive after/during a post-back (AJAX).