动态加载CSS文件

方法一:

< HEAD >
< title > WebForm1 </ title >
< LINK  rel ="stylesheet"  type ="text/css"  href =""  id ="mycss" >
</ HEAD >

private   void  Button1_Click( object  sender, System.EventArgs e)
         {Page.RegisterStartupScript("css",@"<script>mycss.styleSheet.addImport('stylesheet1.css')</script>");
        }  

方法二:--- 戏子的方法..嘻..抄来的...

< HEAD >
         < title > WebForm1 </ title >
         < asp:placeholder  id ="myplaceholder"  runat ="server" ></ asp:placeholder >
     </ HEAD >

private   void  Button2_Click( object  sender, System.EventArgs e)
         {
            System.Web.UI.Control a =  Page.FindControl("myplaceholder");
            System.Web.UI.HtmlControls.HtmlGenericControl objLink = new HtmlGenericControl("LINK");
            objLink.Attributes.Add("rel","stylesheet");
            objLink.Attributes.Add("type","text/css");
            objLink.Attributes.Add("href","StyleSheet1.css");
            objLink=objLink;
            a.Controls.Add(objLink);
        }

[注]  asp:placeholder  这是控件是主要是起"占位符的做用"