webcontrol throws error
 

i have a cs file in my app_code directory with the following code:

using System;
using System.Web.UI.WebControls;

namespace RDK.WebControls
{
public class DepositTypDropDown : DropDownList
{
protected override void OnInit(EventArgs E)
{
base.OnInit(E);
this.Items.Add(new ListItem("Nonrefundable", "NR"));
this.Items.Add(new ListItem("Refundable", "RE"));
this.Items.Add(new ListItem("Option to Purchase", "OP"));
}
public static string GetText(string strValue)
{
DepositTypDropDown ddl = new DepositTypDropDown();
return ddl.Items.FindByValue(strValue).Text; //this line throws the
error
}
}
}


when i try to call the gettext function using:

lblDepositTyp.Text =
DepositTypDropDown.GetText(drQuote["DepositTypId"].ToString());

i get this error:

Object reference not set to an instance of an object.

is there another method i have to call after creating a new instance to get
the list items to be there?