How to determine if a CSS file has been previously registered?

I am writing a Server Custom Control and I am embedding some resources in it.  As part of the process, a CSS resource is copied to the temporary folder.  I then use the following code to register it.

string includeTemplate ="<link rel='stylesheet' text='text/css' href='{0}' />";
string includeLocation = Page.ClientScript.GetWebResourceUrl(this.GetType(), "myStylesheet _Links.css");
LiteralControl include = new LiteralControl(String.Format(includeTemplate, includeLocation));
((System.Web.UI.HtmlControls.HtmlHead)Page.Header).Controls.Add(include);

What I need to do is to determine if the file is already registered with the page.  How can I do this?
DeHaynesAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

crazymanCommented:
(if (Page[this.ClientID] == null)
{
    //not added

Page[this.ClientID] = true;
//your code  
}
0
JunkManCommented:
You're better off using a HtmlLink control instead of a Literal, that way you'll be able to grab it back an check if the reference has been added before or not.
        bool addIt = true;
        string styleSheet = Page.ClientScript.GetWebResourceUrl(this.GetType(), "myStylesheet _Links.css");
        foreach (Control c in Page.Header.Controls)
        {
            HtmlLink l = c as HtmlLink;
            if (null != l && styleSheet.Equals(l.Href, StringComparison.OrdinalIgnoreCase))
            {
                addIt = false;
                break;
            }
        }
        if (addIt)
        {
            HtmlLink link = new HtmlLink();
            link.Href = styleSheet;
            link.Attributes.Add("type", "text/css");
            link.Attributes.Add("rel", "stylesheet");
            Page.Header.Controls.Add(link);
        }

Open in new window

0
rlh68Commented:

    string cssHref = "myStylesheet _Links.css";
    if (!this.Page.IsClientScriptBlockRegistered(cssHref)) {
        string cssScript = "<link rel='stylesheet' text='text/css' href='" + cssHref + "' />";
        this.Page.RegisterClientScriptBlock(cssHref, cssScript);
    }
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
.NET Programming

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.