asp.net查询本地IP

public static string GetIP()
{
string result = String.Empty;
result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (null == result || result == String.Empty)
{
result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
if (null == result || result == String.Empty)
{
result = HttpContext.Current.Request.UserHostAddress;
}
return result;
}