How to access web control from code behind page?

[William Parker]

I have a web control I made called header.ascx. It has its own properties
and methods I defined. But I cannot figure out how to access this control
from my code behind page.

I can create the web control just fine and script with it as needed from the
webform1.aspx page itself just fine, like this:

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false"
Inherits="mysite.WebForm1" %>
<%@ Register TagPrefix="uc1" TagName="header" Src="header.ascx" %>
<uc1:header Title="This is working!!" id="Header1"
runat="server"></uc1:header>
<%
String mytitle = Header1.Title;
Header1.Title = mytitle + " abc";
%>
<uc1:footer id="Footer1" runat="server"></uc1:footer>

But how can I set or get to the web control's properties from the code
behind's Page_Load event instead of directly in the .aspx file? For example
this does NOT work:

private void Page_Load(object sender, System.EventArgs e)
{
String mytitle = Header1.Title;
Header1.Title = mytitle + " abc";
}

When I try that code above I get this error:
"d:\inetpub\wwwroot\mysite\WebForm1.aspx.cs(23): The type or namespace name
'Header1' could not be found (are you missing a using directive or an
assembly reference?)".

If I add a declaration above Page_Load like this "protected
System.Web.UI.UserControl Header1;" then the above error goes away, but then
it complains that Header1 doesn't contain a definition for "Title". This is
because by declaring Header1 in the web form code behind it is obviously
just creating it as a new, blank web control when in fact I am just looking
for a way to reference the one that is created in the .aspx file.

Bottom line is that I want to be able to reference the Header1 web control
created in the .aspx file from my code behind page, but I don't know how I
am supposed to reference or tie in to it. Can someone please help? Thank
you very much.

 

[DalePres]

Make sure you add a declaration for the control in your code-behind class.

Dale

 

[William Parker]

Thanks Dale, but how *exactly* do I go about doing that?

For example in my original post I said this:
"If I add a declaration above Page_Load in the code behind like this
"protected System.Web.UI.UserControl Header1;" then the above error goes
away, but then it complains that Header1 doesn't contain a definition for
"Title". This is because by declaring Header1 in the web form code behind
it is obviously just creating it as a new, blank web control when in fact I
am just looking for a way to reference the one that is created in the .aspx
file. So obviously this is the wrong approach, but the right idea?"

Anyway I am confused how exactly I am support to add a declaration for the
contorl in the code behind which references the user control created in the
..aspx with:
<%@ Register TagPrefix="uc1" TagName="header" Src="header.ascx" %>
<uc1:header Title="This is working!!" id="Header1"

Can you please advise? Thanks!

 

[Saravana [MVP]]

You shouldnt declare that component as system.web.ui.usercontrol in
codebehind, instead you should declare that component as your usercontrol
like <Usercontrolnamespace>.<usercontrolclassname>. So that you can access
your usercontrol properties inside codebehind

 

[Jeffrey Palermo [MCP]]

William,
protected YourNamespace.header Header1;

and then you can access Header1.Title.

You have named your usercontrol with a Type name, and then you access it
through a variable name, so if I have a user control that I have created
<uc1:Header ID="myHeader" runat="server"/>
then in my code behind, I need to declare it:
protected MyNamespace.Header myHeader;

now I can say: myHeader.Title. . .
but if you declare it as UserControl, then you can only access properties of
UserControl, so you need to declare it as the correct custom type.

Best regards,
Jeffrey Palermo

 

[William Parker]

Thank you - this is exactly what I was not understanding, and with this help
it is now working great!!