I want to add css file into head of skin dynamically?

I use this code but don't worked for me.

   protected  void  (EventArgs e)
    {
            HtmlLink css = new HtmlLink();
            css.Href = this.TemplateSourceDirectory + "/style.css";
            css.Attributes["rel"] = "stylesheet";
            css.Attributes["type"] = "text/css";
            Page.Header.Controls.Add(css);
        }

Please advice

I want create skin that exist number color button in it. I want when users click on this buttons happened : 1.create a cookie   with templateCss name and save into name of css file      then 2.  refreshed page  and add  this CSS file into head of skin .  finally user view my site in another colors and  forms. Now I add my css file into head of skin such as this :

<dnn:DnnCssInclude ID="DnnCssInclude9" runat="server" FilePath="css/style.css" PathNameAlias="SkinPath" AddTag="false"    />

Hossein,

you can use "code-behind" that queries the clicked color,something like

<script runat="server">
public void Page_Load(object o, EventArgs e)
{
   // Get Cookie and Apply CSS file, fallback to some default value
}

public void MyColorPicker_Click(object o, EventArgs e)
{
   switch (this.MyColorPicker.Value)
   {
      case "Green":
         // Load green CSS file
         break;
      case "Red":
         // Load Red CSS file
         break;
      ...
      default:
         // Load default CSS file
         break;
   }
   // Set Cookie
}
</script>

Happy DNNing!
Michael