1.防止开放重定向：

 　

/// 
        /// 防止开放重定向        /// 
        ///         /// 
             public static bool IsLocalUrl(string url)        {            if (string.IsNullOrEmpty(url))                return false;            bool result = ((url[0] == '/' && (url.Length == 1 || (url[1] != '/' && url[1] != '\\'))) || (url.Length > 1 && url[0] == '~' && url[1] == '/'));            //绝对路径            if (!result && (url.StartsWith("http:", StringComparison.OrdinalIgnoreCase) || url.StartsWith("https:", StringComparison.OrdinalIgnoreCase)))            {                Uri absoluteUri;                if (Uri.TryCreate(url, UriKind.Absolute, out absoluteUri))                {                    return String.Equals(HttpContext.Current.Request.Url.Host, absoluteUri.Host, StringComparison.OrdinalIgnoreCase);                }            }            return result;            //来自Mvc中的UrlHelper.IsLocalUrl,只能判断相对路径            //!string.IsNullOrEmpty(url) && ((url[0] == '/' && (url.Length == 1 || (url[1] != '/' && url[1] != '\\'))) || (url.Length > 1 && url[0] == '~' && url[1] == '/'));        }

　　

2.使用方法：

public void Login(string userName,string password, string returnUrl){//logic code//validate userName passwordif (!string.IsNullOrEmpty(returnUrl) && Url.IsLocalUrl(returnUrl) ){return Response.Redirect(returnUrl);}return Response.Redirect("/");}