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Catching click event inside an UpdatePanel of a User Control

Posted on 2009-07-06
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Last Modified: 2012-05-07
I was experimenting with dynamically loaded user controls.  

For some reason, when I load (from PickListUser) my PickList control, the control is displayed reasonably - with Region.xml as given, the repeater shows two lines with a name and button on each.

However, when I click the button, ONLY the load code on my host page (PickListUser) is called (with IsPostBack==true), neither the load event nor the click event on the PickList code behind are triggered.
Picklist.ascx:
---------------------------------
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="Picklist.ascx.cs" Inherits="Picklist" %>
<input type="hidden" runat="server" ID="path" />
<input type="hidden"  runat="server" ID="parent" />
<asp:Repeater ID="Repeater1" runat="server" >
<ItemTemplate>
<asp:UpdatePanel runat="server" ID="mypanel" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label runat="server" ID="name" Text='<%# Eval("Name") %>' />
<asp:Button runat="server" ID="select" Text="select"  /><br />
<asp:Label runat="server" ID="display" />
</ContentTemplate>
</asp:UpdatePanel>
</ItemTemplate>
</asp:Repeater>
 
 
Picklist.ascx.cs:
---------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
public partial class Picklist : System.Web.UI.UserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string[] elements = path.Value.Split(',');
            XmlDataSource source = new XmlDataSource();
            source.DataFile = "App_Data/" + elements[0] + ".xml";
            Repeater1.DataSource = source;
            Repeater1.DataBind();
        }
        foreach (RepeaterItem x in Repeater1.Items)
        {
            (x.Controls[1].Controls[0].Controls[3] as Button).Click += Command;
        }
    }
 
 
    protected void Command(object source, EventArgs e)
    {
        display.Text = "foo";
    }
}
 
PickListUser.aspx
---------------------------------
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="PickListUser.aspx.cs" Inherits="PickListUser" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    User!
<asp:ScriptManager runat="server" ID="mgr" />
    </div>
    </form>
</body>
</html>
 
 
PicklistUser.ascx.cs:
---------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
 
public partial class PickListUser : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            Control main = LoadControl("~/Picklist.ascx");
            HtmlInputHidden path = main.FindControl("path") as HtmlInputHidden;
            path.Value = "region,country,call";
            FindControl("form1").Controls.Add(main);
            mgr.RegisterAsyncPostBackControl(main);
        }
    }
}
 
 
Region.xml
---------------------------------
<?xml version="1.0" encoding="utf-8" ?>
<regions>
  <region name="america" id="1" parent="0"/>
  <region name="europe" id="2" parent="0"/>
</regions>

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Question by:Jens Fiederer
2 Comments
 
LVL 96

Accepted Solution

by:
Bob Learned earned 500 total points
ID: 24787982
If you are going to dynamically load the control, then it needs to be loaded all the time.  You must reload the control even if the page posts back, or none of the events will be wired up.
0
 
LVL 23

Author Closing Comment

by:Jens Fiederer
ID: 31600293
Thanks - reloading the whole kibosh did it for me ...  to my surprise, without losing state in the items I was reloading!
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