C#如何获取真实IP地址大家获取用户IP地址常用的方法是 C# 代码   复制  string IpAddress = "";if((HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]!=null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] !=String.Empty) ){        IpAddress=HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] ;}else{         HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"]; }事实上，上面的代码只试用与用户只使用了1层代理，如果用户有2层，3层HTTP_X_FORWARDED_FOR 的值是："本机真实IP,1层代理IP,2层代理IP,....." ，如果这个时候你的数据中保存IP字段的长度很小（15个字节），数据库就报错了。 实际应用中，因为使用多层透明代理的情况比较少，所以这种用户并不多。   获取用户真实IP的方法  C# 代码   复制using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Text.RegularExpressions;namespace Common{    /// <summary>    /// IPAddress 的摘要说明    /// </summary>public class IPAddress : System.Web.UI.Page{    public static Int64 toDenaryIp ( string ip )    {        Int64 _Int64 = 0;        string _ip = ip;        if ( _ip.LastIndexOf ( "." ) > -1 )        {            string[] _iparray = _ip.Split ( ‘.‘ );            _Int64 = Int64.Parse ( _iparray.GetValue ( 0 ).ToString() ) * 256 * 256 * 256 + Int64.Parse ( _iparray.GetValue ( 1 ).ToString() ) * 256 * 256 + Int64.Parse ( _iparray.GetValue ( 2 ).ToString() ) * 256 + Int64.Parse ( _iparray.GetValue ( 3 ).ToString() ) - 1;        }        return _Int64;    }    /// <summary>    /// /ip十进制    /// </summary>    public static Int64 DenaryIp    {        get {            Int64 _Int64 = 0;            string _ip = IP;            if ( _ip.LastIndexOf ( "." ) > -1 )            {                string[] _iparray= _ip.Split ( ‘.‘ );                _Int64 = Int64.Parse ( _iparray.GetValue ( 0 ).ToString() ) * 256 * 256 * 256 + Int64.Parse ( _iparray.GetValue ( 1 ).ToString() ) * 256 * 256 + Int64.Parse ( _iparray.GetValue ( 2 ).ToString() ) * 256 + Int64.Parse ( _iparray.GetValue ( 3 ).ToString() )-1;            }            return _Int64;        }    }    public static string IP    {        get        {            string result = String.Empty;            result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];            if ( result != null && result != String.Empty )            {               //可能有代理                if ( result.IndexOf ( "." ) == -1 ) //没有"."肯定是非IPv4格式                    result = null;                else                {                    if ( result.IndexOf ( "," ) != -1 )                    {                         //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 = 0; i < temparyip.Length; i++ )                        {                            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]; //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                }            }            string IpAddress = ( HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != String.Empty )  HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] : HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];                       if ( null == result || result == String.Empty )                result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];            if ( result == null || result == String.Empty )                result = HttpContext.Current.Request.UserHostAddress;            return result;        }    }     //是否ip格式    public static bool IsIPAddress ( string str1 )    {        if ( str1 == null || str1 == string.Empty || str1.Length < 7 || str1.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 ( str1 );    }}}