UpdatePanel with ASP.NET Repeater and Checkbox Aync Postback issue - asp.net

Question

I have a rather annoying issue here
I can't get my CheckBox CheckedChange event to fire, or catch or whatever it is that fails:
ASPX Code
<asp:UpdatePanel runat="server" ID="udp_Lists" UpdateMode="Always">
<ContentTemplate>
<asp:Repeater ID="rep_showings" runat="server">
<HeaderTemplate>
</HeaderTemplate>
<ItemTemplate>
<div class="div_assignment">
<div class="div_assignment_text">
<asp:LinkButton runat="server" ID="lnk_show_task" OnClick="lnk_show_task_Click" CommandArgument='<%# Eval("Id") %>' Text='<%# Eval("TaskTitle") %>'></asp:LinkButton>
</div>
<div class="div_assignment_checkbox">
<asp:CheckBox runat="server" ID="chk_handle" AutoPostBack="true" OnCheckedChanged="chk_handle_Changed" ToolTip='<%# Eval("Id") %>' />
</div>
</div>
</ItemTemplate>
<FooterTemplate>
</FooterTemplate>
</asp:Repeater>
</ContentTemplate>
<Triggers>
</Triggers>
The Code behind function "chk_handle_Changed" is never reached.
The Linkbutten works perfectly.

Answer 1

I took a look at your problem. I used the following code:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.rep_showings.DataSource = new object[] { new { Title = "title", ID = "id" } };
this.rep_showings.DataBind();
}
}
protected void chk_handle_Changed(object source, EventArgs e)
{
Trace.Write("here");
}
protected void lnk_show_task_Click(object source, EventArgs e)
{
Trace.Write("here 2");
}
protected void rep_showings_ItemCommand(object source, RepeaterCommandEventArgs e)
{ }
The above code works. I think you are probably re-binding your repeater on every postback - I tested this by removing the "if (!IsPostBack)" statement in Page_Load(), and I was able to reproduce the problematic behaviour you describe.
Rebinding a control on every postback should be avoided if possible. Once a control is populated, it's data is taken care of by ViewState, so unless the data is changing, you should probably not be rebinding it all the time.