带编辑的下拉框asp.net

修改了从：http://www.cnblogs.com/ejiyuan/archive/2007/11/09/954325.html的一批文章 生成了可以在Gridview里面调用的CombBox控件，是基于Ajax的。
    独立使用使用方式（）：  <Com:ComboBox ID="ComboBox2" runat="server" Independent="true"  Width="80px" EnableViewState="true">
                    </Com:ComboBox>
在Gridview使用方式（）：  <Com:ComboBox ID="ComboBox2" runat="server" Independent="false"  Width="80px" EnableViewState="true" DataArg='<%Eval("编号") %>'>
                    </Com:ComboBox>
using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Collections;
using System.Web.UI.Design;
[assembly: TagPrefix("Com", "Com")]
namespace Com
{
    /// <summary>
    /// Represents a control that allows the user to select a single item from a drop-down list,
    /// or type in a new value that is not in the list.
    /// </summary>
    /// <remarks>
    /// Since the ComboBox control inherits from <see cref="System.Web.UI.WebControls.ListBox"/>,
    /// you can use it in exactly the same manner (including DataBinding).
    /// For older browsers that do not support the functionality required to render this control,
    /// a normal dropdown box will be emitted instead.
    /// </remarks>
    [ToolboxData("<{0}:ComboBox runat=\"server\"></{0}:ComboBox>")]
    [ValidationPropertyAttribute("SelectedValue")]
    [Designer(typeof(Com.ComboBoxDesigner))]
 &nbs