cascadierende DropDownList an DataList übergeben

Question

Hallo,

ich habe eine kaskadierende DropDownList, die funktioniert (Land, Bundesland, Region). Ich möchte das Ergebnis der Region in DataList ausgeben, aber es gelingt mir leider nicht. War mache ich falsch? Mein Code:

                     <asp:TemplateField>  
                     <ItemTemplate>  
                     <asp:DataList ID="DataListName" runat="server" Text='<%# Eval("Name") %>'>  
                     </asp:DataList>  
                     </ItemTemplate>  
                     </asp:TemplateField>  

und danach:

Protected Sub idRegion_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim strConnString As [String] = ConfigurationManager.ConnectionStrings("conString").ConnectionString
Dim strQuery As [String] = "Select * from Campingplatz where idLand =@LandID and idBundesland = @BundeslandID and idRegion = @RegionID ORDER BY Name ASC"
Dim con As New MySqlConnection(strConnString)
Dim cmd As New MySqlCommand()
cmd.Parameters.AddWithValue("@LandID", MySqlDbType.Decimal).Value = DropDownLand.SelectedItem.Value
cmd.Parameters.AddWithValue("@BundeslandID", MySqlDbType.Decimal).Value = DropDownBundesland.SelectedItem.Value
cmd.Parameters.AddWithValue("@RegionID", MySqlDbType.Decimal).Value = DropDownRegion.SelectedItem.Value
cmd.CommandType = CommandType.Text
cmd.CommandText = strQuery
cmd.Connection = con
Try
con.Open()
DataListName.DataSource = cmd.ExecuteReader()
DataListName.DataBind()
Catch ex As Exception
'Throw ex
Finally
con.Close()
con.Dispose()
End Try
End Sub

Wer kann mir helfen?

Answer 1

Wenn ich DataListName.DataBind() eingebe:

Protected Sub idRegion_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim strConnString As [String] = ConfigurationManager.ConnectionStrings("conString").ConnectionString
    Dim strQuery As [String] = "Select * from Campingplatz where idLand =@LandID and idBundesland = @BundeslandID and idRegion = @RegionID ORDER BY Name ASC"
    Dim con As New MySqlConnection(strConnString)
    Dim cmd As New MySqlCommand()
    cmd.Parameters.AddWithValue("@LandID", MySqlDbType.Decimal).Value = DropDownLand.SelectedItem.Value
    cmd.Parameters.AddWithValue("@BundeslandID", MySqlDbType.Decimal).Value = DropDownBundesland.SelectedItem.Value
    cmd.Parameters.AddWithValue("@RegionID", MySqlDbType.Decimal).Value = DropDownRegion.SelectedItem.Value
    cmd.CommandType = CommandType.Text
    cmd.CommandText = strQuery
    cmd.Connection = con
    Try
        con.Open()
        DataListName.DataSource = cmd.ExecuteReader()
        **DataListName.DataBind()**
    Catch ex As Exception
        'Throw ex
    Finally
            con.Close()
            con.Dispose()
        End Try
End Sub

macht er mir die Tabelle kaputt. Wie verhindere ich das?