Dynamically Register StyleSheet File in ASP.NET

Sometimes it is useful to register an external stylesheet file at runtime dynamically. For example, when we develop portals, this solution can helpful. Because a portal is a comprehensive web based application and a portal user must be able to implement its requirements.

I have a class in my portal that contains useful functions. The name of the class is Functions. In this class, I have many functions that help impement my requirements in a portal. The register stylesheet function is as follows:

public static bool registerStyleSheetFileDynamic(string styleSheetFilePath, System.Web.UI.Page page)
{
 styleSheetFilePath = page.ResolveClientUrl(styleSheetFilePath);
 if (page != null)
 {
  System.Web.UI.HtmlControls.HtmlHead head = (System.Web.UI.HtmlControls.HtmlHead)page.Header;
  bool isExistStyleSheet = false;
  //head.StyleSheet.RegisterStyle(
  foreach (System.Web.UI.Control item in head.Controls)
  {
    if (item is System.Web.UI.HtmlControls.HtmlLink && 
          ((System.Web.UI.HtmlControls.HtmlLink)item).Attributes["href"] == styleSheetFilePath)
     {
      isExistStyleSheet = true;
     }
  }
  if (!isExistStyleSheet)
  {
   System.Web.UI.HtmlControls.HtmlLink link = new System.Web.UI.HtmlControls.HtmlLink();
   link.Attributes.Add("href", page.ResolveClientUrl(styleSheetFilePath));
   link.Attributes.Add("type", "text/css");
   link.Attributes.Add("rel", "stylesheet");
   head.Controls.Add(link);
  }
  return true;
 }
 return false;
}

In this case I can send my arbitrary page and path of stylesheet file to this method in any point in my portal page and so on. I hope the other parts are clear. Thanks!