取得用户IP

/// <summary>
/// 取得用户IP
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public static string GetUserIpAddress(BmhdContext context)
{
    string result = String.Empty;
    if (context == null) 
        return result;

    result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
    if (null == result || result == String.Empty)
        result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

    return result;
}