Howto create a custom control

Hi!

At the moment, I'm trying to create a custom 'asp.net server control' (a .CS!! not an ASCX!!), which should contain some DevExpress asp.net controls. As a simple example, I'm just trying to render a ASPxTextbox within my custom control.

When being rendered, I get the following javascript error :

"Microsoft JScript runtime error: 'ASPxClientTextBox' is undefined"

So, I guessed some initialitation scripts are missing. Then I tried to including this base script by calling :

ASPxTextBox.RegisterBaseScript(this.Page);

This however did not work; the same javascript error still occurs.

The full code if my simple example custom control can be found below:
-------------------------------------------------------------

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using DevExpress.Web.ASPxCallback;
using DevExpress.Web.ASPxPopupControl;
using DevExpress.Web.ASPxGridView;
using System.Drawing;
using System.Web.UI.HtmlControls;
using DevExpress.Web.ASPxEditors;
using DevExpress.Web.ASPxClasses;

namespace TypeSelector
{
    [DefaultProperty("OutputType")]
    [ToolboxData("<{0}:TypeSelector runat=server></{0}:TypeSelector>")]
    public class TypeSelector : WebControl
    {

        private ASPxTextBox textboxResult = new ASPxTextBox();

   
        #region Public properties

        public string OutputType
        {
            get
            {
                String s = (String)ViewState["OutputType"];
                return s;
            }

            set
            {
                ViewState["OutputType"] = value;
            }
        }

        #endregion

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            ASPxTextBox.RegisterBaseScript(this.Page);
        }

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);

            //textbox
            textboxResult.ID = this.ID + "TextboxResult";
            textboxResult.Font.Size = FontUnit.XXSmall;
            textboxResult.ReadOnly = true;
            textboxResult.Width = Unit.Pixel(170);

        }

        protected override void RenderContents(HtmlTextWriter output)
        {
            output.Write(OutputType);
            textboxResult.RenderControl(output);
            
        }
    }
}