SelectedIndexChanged not firing in ascx? - asp.net

Question

I use masterpage.In ascx page my selectedindexchange event not firing.
This is my code:
My ascx :
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="FilterList.ascx.cs"
Inherits="F8.B2B.WEB.UserControls.Common.FilterList.FilterList" %>
<asp:UpdatePanel UpdateMode="Always" runat="server">
<ContentTemplate>
<div id="filterList" runat="server">
</div>
</ContentTemplate>
</asp:UpdatePanel>
My ascx.cs:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
createFilterLists();
}
}
private void createFilterLists()
{
ListBox dpList = new ListBox()
{
ID = ControlID
};
dpList.Items.Clear();
if (lst_ListItem != null)
{
foreach (ListItem item_ in lst_ListItem)
{
dpList.Items.Add(item_);
}
dpList.Items[0].Selected = true;
dpList.AutoPostBack = true;
dpList.EnableViewState = true;
dpList.SelectedIndexChanged += new EventHandler(myListBox_SelectedIndexChanged);
filterList.Controls.Add(dpList);
}
}
protected void myListBox_SelectedIndexChanged(object sender, EventArgs e)
{
// might be entered on change
}

Answer 1

Because your list box is dynamically generated by code, you need to add it in every page load even if it is a postback.

Answer 2

Create dynamic controls and add event handlers in the OnInit event
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
CreateControls();
myDataGrid.SomeEventHandler += new ...
}
Bind data and fill controls in the OnLoad event
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
FillControls();
myDataGrid.DataSource = somedatasource;
myDataGrid.DataBind();
}
}
private void CreateControls()
{
ListBox dpList = new ListBox()
{
ID = ControlID
};
dpList.AutoPostBack = true;
dpList.EnableViewState = true;
dpList.SelectedIndexChanged += new EventHandler(myListBox_SelectedIndexChanged);
filterList.Controls.Add(dpList);
}
private void FillControls()
{
dpList.Items.Clear();
if (lst_ListItem != null && lst_ListItem.Count > 0)
{
foreach (ListItem item_ in lst_ListItem)
{
dpList.Items.Add(item_);
}
dpList.Items[0].Selected = true;
}
}