I am stuggling with databinding a drop down list, hooking into the SelectedIndexCh anged and attempting to avoid using the viewstate.
The drop down list is quite large so I would prefer to avoid using the view state so I set EnableViewState on the page to false. To enable the drop down list to bind to a datasource I bind it during the OnInit.
I do a response.Write during the SelectedIndexCh anged event to verify that the event fires.
It all works EXCEPT when the first item of the drop down list is reselected after another item is selected. The event just does not fire.
Does this mean that if you want to hook into SelectedIndexCh anged reliably you must use the ViewState?
Regards
Dave A
<%@ Page language="c#" Codebehind="Web Form1.aspx.cs" AutoEventWireup ="false" Inherits="WebAp plication1.WebF orm1" enableViewState ="False"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>WebForm1 </title>
<meta name="GENERATOR " Content="Micros oft Visual Studio .NET 7.1">
<meta name="CODE_LANG UAGE" Content="C#">
<meta name="vs_defaul tClientScript" content="JavaSc ript">
<meta name="vs_target Schema" content="http://schemas.microso ft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING= "GridLayout ">
<form id="Form1" method="post" runat="server">
<asp:DropDownLi st id="DropDownLis t1" style="Z-INDEX: 101; LEFT: 96px; POSITION: absolute; TOP: 72px"
runat="server" Width="280px" AutoPostBack="T rue"></asp:DropDownLis t>
</form>
</body>
</HTML>
----
using System;
using System.Collecti ons;
using System.Collecti ons.Specialized ;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.Sess ionState;
using System.Web.UI;
using System.Web.UI.W ebControls;
using System.Web.UI.H tmlControls;
namespace WebApplication1
{
/// <summary>
/// Summary description for WebForm1.
/// </summary>
public class WebForm1 : System.Web.UI.P age
{
protected System.Web.UI.W ebControls.Drop DownList DropDownList1;
NameValueCollec tion list = new NameValueCollec tion();
protected WebForm1()
{
list.Add("Do not filter","");
list.Add("abc", "1");
list.Add("def", "2");
list.Add("ghi", "3");
list.Add("jkl", "4");
}
private void Page_Load(objec t sender, System.EventArg s e)
{
}
#region Web Form Designer generated code
override protected void OnInit(EventArg s e)
{
DropDownList1.D ataSource = list;
DropDownList1.D ataBind();
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeCompo nent();
base.OnInit(e);
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.DropDownLi st1.SelectedInd exChanged += new System.EventHan dler(this.DropD ownList1_Select edIndexChanged) ;
this.Load += new System.EventHan dler(this.Page_ Load);
}
#endregion
private void DropDownList1_S electedIndexCha nged(object sender, System.EventArg s e)
{
Response.Write( "Drop down list fired:" + DropDownList1.S electedValue);
}
}
}
