ASP.NET Custom Control - What is the best way to include embedded CSS reference only once?

Question

The problem: I am embedding a CSS file into a custom control library with several controls. I want to share the same CSS file for all of the controls regardless of how many

Answer 1

To prevent duplication when emitting css files from server controls, we do the following:

if (!Page.ClientScript.IsClientScriptBlockRegistered("SoPro." + id)) {
    HtmlLink cssLink = new HtmlLink();
    cssLink.Href = cssLink.Href = Page.ClientScript.GetWebResourceUrl(this.GetType(), styleSheet);
    cssLink.Attributes.Add("rel", "stylesheet");
    cssLink.Attributes.Add("type", "text/css");
    this.Page.Header.Controls.Add(cssLink);
    this.Page.ClientScript.RegisterClientScriptBlock(typeof(System.Web.UI.Page), "SoPro." + id, String.Empty);
}

First we test to see if the named script was previously registered. If not, we add it in.