I am trying to databind a rad tree to a table that I create from a database. I followed the video example and changed the way I populate the table, but I know I am getting the correct data back. However, I get this error

Server Error in '/' Application.

---

Object reference not set to an instance of an object.

Line 14:         
Line 15:             ' CreateChildControls the Table and assign the datasource
Line 16:             RadTreeView1.DataSource = CreateTable()
Line 17:             ' Assign the data fields
Line 18:             RadTreeView1.DataFieldID = "ID"

[NullReferenceException: Object reference not set to an instance of an object.]
   ASP.clickablecommunity_master.Page_Load(Object sender, EventArgs e) in c:\websites\ClickableCommunity\ClickableCommunity.Master:16
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +47
   System.Web.UI.Control.LoadRecursive() +131
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

Here is the vb code

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        
        If Not Page.IsPostBack Then
        
            ' CreateChildControls the Table and assign the datasource
            RadTreeView1.DataSource = CreateTable()
            ' Assign the data fields
            RadTreeView1.DataFieldID = "ID"
            RadTreeView1.DataFieldParentID = "ParentID"
            RadTreeView1.DataTextField = "Text"
            ' Bind the data
            RadTreeView1.DataBind()
            
        End If
    End Sub 'page_load
    
    'this function creates a datatable for the rad
    'tree that is in the events panel
    Private Function CreateTable() As DataTable
        'set up my connection to the database
        Dim conn As New SqlConnection
        conn.ConnectionString = ConfigurationManager.ConnectionStrings("connectionString").ConnectionString

        Dim table As DataTable = New DataTable()
        table.Columns.Add("ID")
        table.Columns.Add("ParentID")
        table.Columns.Add("Text")

        'this is a counter for the id fields
        'of the data table
        Dim count As Integer = 0
        
        'this adds the parent categories to the 
        'datatable
        Dim categoryQuery As New SqlCommand
        conn.Open()
        categoryQuery.Connection = conn
        categoryQuery.CommandText = "select CategoryId, Name from categories"
        Dim cdr As SqlDataReader = categoryQuery.ExecuteReader()
        While cdr.Read()
            
            If (cdr.Item(0).ToString <> "") Then
                
                table.Rows.Add(New String() {count.ToString, count.ToString, cdr.Item(1).ToString})
                
                'we have to increment count to keep an id for the data table
                count = count + 1
                
            End If
            
        End While 'while cdr.Read()
        conn.Close()
        conn.Open()
        'this adds the events with their parent category
        'id to the datatable
        Dim eventQuery As New SqlCommand
        eventQuery.Connection = conn
        eventQuery.CommandText = "SELECT eventid, FK_CategoryID, name from events"
        Dim edr As SqlDataReader = eventQuery.ExecuteReader()
        While edr.Read()
            
            If (edr.Item(0).ToString <> "") Then
                
                table.Rows.Add(New String() {count.ToString(), edr.Item(1).ToString, edr.Item(2).ToString})
                
                'we have to increment count to keep an id for the data table
                count = count + 1
                
            End If
            
        End While 'while edr.Read()
        
        Return table

    End Function 'CreateGenreTable

What I can't understand is why it says that createtable is null. I am returning the table and I have outputted the data that I am adding to the table. Any ideas? Thanks

I tried surrounding the rsAvOptionsScroll div in the AdvancedForm with a UpdatePanel:

        <asp:UpdatePanel ID="updtAdvFormControls" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="false">
        <ContentTemplate>

Then I tried dropping a standard Button and a RadTextBox on the form:

        <asp:Button ID="btnResetSearch" runat="server" Text="Reset" OnClick="AddTeamMember2" Style="text-align: center;" />

        <telerik:RadTextBox ID="RadTextBox1" runat="server">
        </telerik:RadTextBox>

After that I created the callback function:

        protected void AddTeamMember2(object sender, EventArgs e)
        {
            RadTextBox1.Text = "hhh";
            updtAdvFormControls.Update();
        }

When I clicked on the button the debugger goes into the AddTeamMember2 function
but the RadTextBox1 never gets set to "hhh" after it you hit F5 to continue. If I type in
"xxx" in the RadTextBox1 from the screen and then take the debugger back into the
AddTeamMember2 function, the value is set to "xxx" and latter gets set to "hhh" but
after hitting F5 to continue the screen always says "xxx".

Thanks,

Kip