User control question

scott_rider · May 19th, 2008, 12:50 PM

I'm trying to dynamically load user controls based on click events. But, for some reason lb_websites in (listed below) header.ascx's click event doesn't register as being invoked. Thanks in advance.

Default5.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default5.aspx.cs" Inherits="Default5" %>
<%@ Register Src="~\user_controls\blank.ascx" TagName="header" TagPrefix="uc" %>
<%@ Register Src="~\user_controls\blank.ascx" TagName="menu" TagPrefix="uc" %>

<!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>Untitled Page</title>
    <link href="cms.css" rel="stylesheet" type="text/css" />
</head>
<body>
<form id="frame_form" runat="server">
<div id="header_area" class="header_area" runat="server"><uc:header ID="wuc_header" runat="server" /></div>
<div id="main_area" class="main_area" runat="server">
    <div id="menu" class="menu" runat="server"><uc:menu ID="wuc_menu" runat="server" /></div>
</div>
</form>
</body>
</html>

Default5.aspx.cs
using System;
using System.Collections;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Default5 : System.Web.UI.Page {

    protected void Page_Load(object sender, EventArgs e) {
        header_area.Controls.Add(LoadControl(@"~/user_controls/header.ascx"));
        if (Page.IsPostBack) {
            this.wuc_header.clicked += new blank.OnButtonClick(default_click);
            this.wuc_menu.clicked += new blank.OnButtonClick(default_click);
        }
    }
    void default_click(string button_text) {
        // loading controls
    }
}

blank.ascx.cs
using System;

public partial class blank : System.Web.UI.UserControl {

    // Delegate declaration
    public delegate void OnButtonClick(string button_clicked);

    // Event declaration
    public event OnButtonClick clicked;
}

header.ascx
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="~/user_controls/header.ascx.cs" Inherits="header" %>
<asp:LinkButton ID="lb_websites" runat="server" Text="websites" OnClick="lb_Click" />
<asp:LinkButton ID="lb_administration" runat="server" Text="administration" OnClick="lb_Click" />

header.ascx.cs
using System;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class header : System.Web.UI.UserControl {

    // Delegate declaration
    public delegate void OnButtonClick(string button_clicked);

    // Event declaration
    public event OnButtonClick clicked;

    protected void Page_Load(object sender, EventArgs e) { }

    protected void lb_Click(object sender, EventArgs e) {
        // Check if event is null
        if (clicked != null) clicked(((LinkButton)sender).Text);
    }
}

planoie · May 19th, 2008, 03:35 PM

This code is rather confusing:

1) default_click is in a place that doesn't permit the file to compile. I can only assume it is supposed to be part of the class "Default5".

2) You posted code for "blank.ascx.cs", but where is the ASCX file?

3) You needn't register the same user control file (blank.ascx) twice. You can reuse a single control in the page.

4) You have declared a delegate and event in both the "header" class and the "blank" class. This greatly confused the issue but I think I see why it is in there twice. I would guess that you added in the same delegate and event in blank in the hopes it would result in the automatic bubbling of the event. Unfortunately, it doesn't work that way.

In this line:

Code:

   header_area.Controls.Add(LoadControl(@"~/user_controls/header.ascx"));

you are creating a new instance of "header" which has the link buttons. You add this to the "header_area" div control. But then you wire the button click handler to the clicked events of your blank placeholder control instances (header, menu) instead of the actual header control. There is nothing in the "blank" class that ever calls those events.

A fix is to save off the instance of the header control you load so that you can wire up to its events:

Code:

   header myHeader;
   myHeader = (header)LoadControl(@"~/user_controls/header.ascx");
   header_area.Controls.Add(myHeader);
   if(Page.IsPostBack)
   {
      myHeader.clicked += new header.OnButtonClick(default_click);
   }

Incidentally, the <asp:panel> renders as a DIV tag. Alternatively, if all you really need is a control placeholder, try the <asp:placeholder> control which renders no HTML.

-Peter
compiledthoughts.com

scott_rider · May 19th, 2008, 04:23 PM

You are correct on the default_click. Sorry. I stripped out some code and should have seen that. Here is the remaining piece.

blank.ascx
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="blank.ascx.cs" Inherits="blank" %>

scott_rider · May 19th, 2008, 04:38 PM

I'm going to integrate your info and should have some questions in a few minutes.

scott_rider · May 19th, 2008, 04:59 PM

How do I add partial class c_menu into my project?

scott_rider · May 20th, 2008, 08:36 AM

Anybody?

planoie · May 20th, 2008, 03:59 PM

Where did "c_menu" come from? Did you have success with my suggestion?

-Peter
compiledthoughts.com