LiteralControl 控件实现动态添加CSS

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class CommonQuery_PageRegStyle : System.Web.UI.Page
{
    protected string strAlert = "Hello, Happy New Year!";
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected override void OnPreRender(EventArgs e)
    {
        
        string cssFrageMent = "<style type='text/css'> "
                               + ".CommonQueryBtn {"
                               + "  border:0; width:64px;height:20px;background:url('"
                               + HttpRuntime.AppDomainAppVirtualPath + @"/images/BUTTON/btn.jpg');"
                               +"     }</style>";
        LiteralControl include = new LiteralControl(cssFrageMent);        
        this.Page.Header.Controls.Add(include);
        base.OnPreRender(e);
    }
}