asp.net 301重定向代码

/// <summary>
    ///重定向代码
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    void Application_BeginRequest(object sender, EventArgs e)
    {
        Uri url = Request.Url;
        string host = url.Host.ToLower();

        string strWebURL = "www.yuming.com";//此处是带www.的域名
        if (url.AbsoluteUri.IndexOf(strWebURL) == -)
        {
            Response.Status = "301 Moved Permanently";
            // 避免替换掉后面的参数中的域名
            Response.AddHeader("Location", url.AbsoluteUri.Replace(string.Format("http://{0}", host), string.Format("http://www.{0}", host)));
            Response.End();
        }
    }