I have a custom control and I want to dynamically insert a link to a stylesheet.
Might not be the best solution of the year but it needs to be done. Any idea how to do it?
Everytime I try, Page.Header is null.
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At what point during the page life cycle are you trying to access the Page.Header?Nathan Taylor– Nathan Taylor2010-04-14 20:18:33 +00:00Commented Apr 14, 2010 at 20:18
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4 Answers
Here's how you would normally add a CSS programatically:
protected void Page_Init(object sender, EventArgs e)
{
var link = new HtmlLink();
link.Href = "~/styles/main.css";
link.Attributes.Add("rel", "stylesheet");
link.Attributes.Add("type", "text/css");
Page.Header.Controls.Add(link);
}
You might need to put a runat="server" in the head tag:
<head runat="server">
<title>Add CSS example</title>
</head>
3 Comments
Maxime Rouiller
Got it. I was missing the Runat="Server" in the header tag of my masterpage. :) Thank you!
Peter
Wouldn't this be a problem if you added the control, say, 10 times on your page? Then the CSS file would be linked 10 times.
Darin Dimitrov
@Peter, yes I guess that would be problematic.
To avoid the problem of multiple stylesheets when adding the control 10 times to the page, change the above code slightly:
string styleSheet = "stylesheetName.css";
if (this.Page.Header.FindControl(styleSheet) == null)
{
HtmlLink cssLink = new HtmlLink();
cssLink.ID = styleSheet;
cssLink.Href = "~/styles/" + styleSheet;
cssLink.Attributes.Add("rel", "stylesheet");
cssLink.Attributes.Add("type", "text/css");
this.Page.Header.Controls.Add(cssLink);
}
By giving the control an ID you can check if it already exists, and so ensure that you only add it the once.
Comments
If you are dynamic css in head tag it wont work, you need to paste the css link tag in the body tag then it may work
1 Comment
raw_hitt
exactly if you adding dynamic url, the it won't work in head tag
I know this question have already accepted an answer. I recently went through the same error. The javascript/Css with <% %> tags from the head can give you error. Removing ASP tags <% %> from head fixes this error.
I was getting the same error in a weird way, I had css files in master page, It used to work for the first page but on the second page after redirecting, I was getting error. So I removed the css link from head tag and pasted it at the end of form tag.
http://italez.wordpress.com/2010/06/22/ajaxcontroltoolkit-calendarextender-e-strana-eccezione/