Is it possible to populate a multiselect in a Form from DB?

I have defined a form in a layout. In this form, I have a MultiSelect field :

  { type: "multiselect", name: "Apps", connector: "http://localhost/test.ashx" }

I want the data in the multiselect to be retrieved from database. I have seen examples of that using a PHP connector, but when I try to create a .NET Connector (serverside), it fails with

my ashx code is

[code] public class ApplicationsList : dhtmlxRequestHandler
public override IdhtmlxConnector CreateConnector(HttpContext context)
{ dhtmlxOptionsConnector connector = new dhtmlxOptionsConnector(
“SELECT col1 , col2 from dpl_app where app_cat<>‘X’ and app1_seq > 0 order by col1”,
“col2”, //PK

          dhtmlxDatabaseAdapterType.Odbc, //predefined database adapter type
                                          //connection string


        return connector;

    public new bool IsReusable
            return false;

It seems that dhtmlxOptionsConnector is not the right connector to use, but which one should I use ?
Thanks for any info,