简单的访客IP获取类-IPHelper.cs

 public class IPHelper
 {
     public static string GetVisitorsIPAddress()
     {
         string result = String.Empty;

         result = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

         // 如果使用代理，获取真实IP
         if (result != null && result.IndexOf(".") == -)    //没有“.”肯定是非IPv4格式
             result = null;
         else if (result != null)
         {
             if (result.IndexOf(",") != -)
             {
                 //有“,”，估计多个代理。取第一个不是内网的IP。
                 result = result.Replace(" ", "").Replace("'", "");
                 string[] temparyip = result.Split(",;".ToCharArray());
                 for (int i = ; i < temparyip.Length; i++)
                 {
                     if (IsIPAddress(temparyip[i])
                         && temparyip[i].Substring(, ) != "10."
                         && temparyip[i].Substring(, ) != "192.168"
                         && temparyip[i].Substring(, ) != "172.16.")
                     {
                         return temparyip[i];    //找到不是内网的地址
                     }
                 }
             }
             else if (IsIPAddress(result)) //代理即是IP格式
                 return result;
             else
                 result = null;    //代理中的内容 非IP，取IP
         }
         if (null == result || result == String.Empty)
             result = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

         if (result == null || result == String.Empty)
             result = System.Web.HttpContext.Current.Request.UserHostAddress;

         return result;
     }

     /// <summary>
     /// 判断是否是IP地址格式 0.0.0.0
     /// </summary>
     /// <param name="str1">待判断的IP地址</param>
     /// <returns>true or false</returns>
     private static bool IsIPAddress(string str1)
     {
         if (str1 == null || str1 == string.Empty || str1.Length <  || str1.Length > ) 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(str1);
     }
 }