Problemas con un DropDownList

[fitog4]

Creo que el problema no viene de ahi:


Os paso el codigo a ver que os parece:

Código:

Imports System.Web.UI
Imports System.Collections.Generic
Imports System.Reflection
Imports System.Data


Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Not IsPostBack Then

            TipoUsuarioddl.Items.Insert(0, New ListItem("-tipo usuario-", ""))
            TipoUsuarioddl.Items.Insert(1, New ListItem("Escuela Idioma", ""))
            TipoUsuarioddl.Items.Insert(2, New ListItem("Alojamiento", ""))
            TipoUsuarioddl.Items.Insert(3, New ListItem("Demandante", ""))
            TipoUsuarioddl.Items.Insert(4, New ListItem("Alumno", ""))

        End If
    End Sub

    Public Sub TipoUsuarioddl_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TipoUsuarioddl.SelectedIndexChanged
        Select Case TipoUsuarioddl.SelectedIndex
            Case 0
                Dim dt As DataTable = New DataTable()

                dt.Columns.Add(New DataColumn("Text", GetType(String)))
                dt.Columns.Add(New DataColumn("Value", GetType(String)))

                dt.Rows.Add(CreateRow("-tipo-", "0", dt))

                Tipoddl.DataSource = dt
                Tipoddl.DataBind()
                Tipoddl.Enabled = False
            Case 1
                Tipoddl.Enabled = True
                Dim dt As DataTable = New DataTable()

                dt.Columns.Add(New DataColumn("Text", GetType(String)))
                dt.Columns.Add(New DataColumn("Value", GetType(String)))

                dt.Rows.Add(CreateRow("-tipo-", "0", dt))
                dt.Rows.Add(CreateRow("Universidad", "1", dt))
                dt.Rows.Add(CreateRow("Academia", "2", dt))

                Tipoddl.DataSource = dt
                Tipoddl.DataBind()
            Case 2
                Tipoddl.Enabled = True
                Dim dt As DataTable = New DataTable()

                dt.Columns.Add(New DataColumn("Text", GetType(String)))
                dt.Columns.Add(New DataColumn("Value", GetType(String)))

                dt.Rows.Add(CreateRow("-tipo-", "0", dt))
                dt.Rows.Add(CreateRow("Apartamentos / Piso compartido", "1", dt))
                dt.Rows.Add(CreateRow("Residencias", "2", dt))
                dt.Rows.Add(CreateRow("Familia", "3", dt))
                dt.Rows.Add(CreateRow("Hotel", "4", dt))

                Tipoddl.DataSource = dt
                Tipoddl.DataBind()
            Case 3
                Dim dt As DataTable = New DataTable()

                dt.Columns.Add(New DataColumn("Text", GetType(String)))
                dt.Columns.Add(New DataColumn("Value", GetType(String)))

                dt.Rows.Add(CreateRow("-tipo-", "0", dt))

                Tipoddl.DataSource = dt
                Tipoddl.DataBind()
                Tipoddl.Enabled = False
            Case 4
                Dim dt As DataTable = New DataTable()

                dt.Columns.Add(New DataColumn("Text", GetType(String)))
                dt.Columns.Add(New DataColumn("Value", GetType(String)))

                dt.Rows.Add(CreateRow("-tipo-", "0", dt))

                Tipoddl.DataSource = dt
                Tipoddl.DataBind()
                Tipoddl.Enabled = False

        End Select


    End Sub
    Function CreateRow(ByVal Text As String, ByVal Value As String, ByVal dt As DataTable) As DataRow
        Dim dr As DataRow = dt.NewRow()

        dr(0) = Text
        dr(1) = Value

        Return dr
    End Function


End Class

Gracias