Answer by pr0gg3r for System.Net.WebException HTTP status code

this works only if WebResponse is a HttpWebResponse.

try{    ...}catch (System.Net.WebException exc){    var webResponse = exc.Response as System.Net.HttpWebResponse;    if (webResponse != null &&         webResponse.StatusCode == System.Net.HttpStatusCode.Unauthorized)    {        MessageBox.Show("401");    }    else        throw;}