MVC 获取真实ip地址

/// <summary>  
       /// 获取真ip  
       /// </summary>  
       /// <returns></returns>  
       public  string GetRealIP()  
       {  
           string result = String.Empty;   
           result = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];  
           //可能有代理   
           if (!string.IsNullOrWhiteSpace(result))  
           {  
               //没有"." 肯定是非IP格式  
               if (result.IndexOf(".") == -1)  
               {  
                   result = null;  
               }  
               else  
               {  
                   //有","，估计多个代理。取第一个不是内网的IP。  
                   if (result.IndexOf(",") != -1)  
                   {  
                       result = result.Replace(" ", string.Empty).Replace("\"", string.Empty);  
  
                       string[] temparyip = result.Split(",;".ToCharArray());  
  
                       if (temparyip != null && temparyip.Length > 0)  
                       {  
                           for (int i = 0; i < temparyip.Length; i++)  
                           {  
                               //找到不是内网的地址  
                               if (IsIPAddress(temparyip[i]) && temparyip[i].Substring(0, 3) != "10." && temparyip[i].Substring(0, 7) != "192.168"&& temparyip[i].Substring(0, 7) != "172.16.")  
                               {  
                                   return temparyip[i];  
                               }  
                           }  
                       }  
                   }  
                   //代理即是IP格式  
                   else if (IsIPAddress(result))  
                   {  
                       return result;  
                   }  
                   //代理中的内容非IP  
                   else  
                   {  
                       result = null;  
                   }  
               }  
           }  
  
           if (string.IsNullOrWhiteSpace(result))  
           {  
               result = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];  
           }  
  
           if (string.IsNullOrWhiteSpace(result))  
           {  
               result = System.Web.HttpContext.Current.Request.UserHostAddress;  
           }  
           return result;  
       }  
       public  bool IsIPAddress(string str)  
       {  
           if (string.IsNullOrWhiteSpace(str) || str.Length < 7 || str.Length > 15)  
               return false;  
  
           string regformat = @"^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})";   
           Regex regex = new Regex(regformat, RegexOptions.IgnoreCase);  
  
           return regex.IsMatch(str);  
       }