问对于MVC 6 ASP.NET 5，IPAddress为空

EN

if (httpContext.Connection.RemoteIpAddress != null)
{
     currentIp = httpContext.Connection.RemoteIpAddress.ToString();
}

    private static string GetIPAddress(HttpRequest httpRequest)
    {
        string keys = string.Empty;
        foreach (string key in httpRequest.Headers.Keys)
        {
            keys = keys + key + "#";
        }

        string[] arrKeys = keys.Split('#');

        int x = 0;
        foreach (string value in httpRequest.Headers.Values)
        {
            if (arrKeys[x].Trim() == "X-Forwarded-For")
            {
                string[] arrIP = value.Split(':');
                if (arrIP[0] != null)
                {
                    // ip found
                    return arrIP[0];
                }
            }
            x++;
        }

        // no ip found
        return string.Empty;
    }