You can check if the error is of type WebException
and then inspect the response code;
if (e.Error.GetType().Name == "WebException")
{
WebException we = (WebException)e.Error;
HttpWebResponse response = (System.Net.HttpWebResponse)we.Response;
if (response.StatusCode==HttpStatusCode.NotFound)
System.Diagnostics.Debug.WriteLine("Not found!");
}
or
try
{
// send request
}
catch (WebException e)
{
// check e.Status as above etc..
}