C# identifies whether url is a network path

#region 识别urlStr是否是网络路径  
      /// <summary>  
      /// 识别urlStr是否是网络路径  
      /// </summary>  
      /// <param name="urlStr"></param>  
      /// <returns></returns>  
      public static bool UrlDiscern(string urlStr)  
      {  
          if (Regex.IsMatch(urlStr, @"((http|ftp|https)://)(([a-zA-Z0-9\._-]+\.[a-zA-Z]{2,6})|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))(:[0-9]{1,4})*(/[a-zA-Z0-9\&%_\./-~-]*)?"))  
          {  
              return true;  
          }  
          else 
          {  
              return false;  
          }  
      }  
      #endregion