C# HTTP状态码

using System.Net;public ActionResult Test(){    try    { }    catch (WebException ex)    {        HttpWebResponse res = (HttpWebResponse)ex.Response;        if (res.StatusCode == HttpStatusCode.OK) //200        { }        else if (res.StatusCode == HttpStatusCode.BadRequest)//400        { }        else if (res.StatusCode == HttpStatusCode.NotFound)//404        { }        else if (res.StatusCode == HttpStatusCode.InternalServerError)//500        { }        else        { }        throw ex;    }    return View();}