AJAX WAS Here - Part 3 : Auto Complete TextBox

using System;
using System.Web;

namespace WCPierce.Web
{
	public sealed class CallBackHelper
	{
		private CallBackHelper() { }

    public static bool IsCallBack
    {
      get
      {
        HttpRequest hr = CallBackHelper.GetHttpRequest();
        return hr.Params["IsCallBack"] != null;
      }
    }

    public static void Write( string Text )
    {
      HttpResponse hr = CallBackHelper.GetHttpResponse();
      
      hr.Clear();
      hr.StatusCode = 200;
      hr.StatusDescription = "OK";
      hr.Write( Text );
      hr.Flush();
      hr.End();
    }

    public static void HandleError( Exception e )
    {
      HttpResponse hr = CallBackHelper.GetHttpResponse();

      hr.Clear();
      hr.StatusCode = 200;
      hr.StatusDescription = "ERROR";
      hr.Write( e.ToString() );
      hr.Flush();
      hr.End();
    }

    private static HttpResponse GetHttpResponse()
    {
      HttpResponse hr = null;
      try
      {
        hr = System.Web.HttpContext.Current.Response;
      }
      catch( NullReferenceException nre )
      {
        throw new Exception("CallBackHelper could not access current HttpResponse object", nre);
      }

      return hr;
    }

    private static HttpRequest GetHttpRequest()
    {
      HttpRequest hr = null;
      try
      {
        hr = System.Web.HttpContext.Current.Request;
      }
      catch( NullReferenceException nre )
      {
        throw new Exception("CallBackHelper could not access current HttpRequest object", nre);
      }

      return hr;
    }
	}
}