How to get status code from webclient?

user_355801 0
Viewed 127727

I am using the WebClient class to post some data to a web form. I would like to get the response status code of the form submission. So far I've found out how to get the status code if there is a exception

Catch wex As WebException
        If TypeOf wex.Response Is HttpWebResponse Then
          msgbox(DirectCast(wex.Response, HttpWebResponse).StatusCode)
            End If

However if the form is submitted successfully and no exception is thrown then I won't know the status code(200,301,302,...)

Is there some way to get the status code when there is no exceptions thrown?

PS: I prefer not to use httpwebrequest/httpwebresponse

webclient vb.net .net c#
10 Answers

Erik's answer doesn't work on Windows Phone as is. The following does:

class WebClientEx : WebClient
{
    private WebResponse m_Resp = null;

    protected override WebResponse GetWebResponse(WebRequest Req, IAsyncResult ar)
    {
        try
        {
            this.m_Resp = base.GetWebResponse(request);
        }
        catch (WebException ex)
        {
            if (this.m_Resp == null)
                this.m_Resp = ex.Response;
        }
        return this.m_Resp;
    }

    public HttpStatusCode StatusCode
    {
        get
        {
            if (m_Resp != null && m_Resp is HttpWebResponse)
                return (m_Resp as HttpWebResponse).StatusCode;
            else
                return HttpStatusCode.OK;
        }
    }
}

At least it does when using OpenReadAsync; for other xxxAsync methods, careful testing would be highly recommended. The framework calls GetWebResponse somewhere along the code path; all one needs to do is capture and cache the response object.

The fallback code is 200 in this snippet because genuine HTTP errors - 500, 404, etc - are reported as exceptions anyway. The purpose of this trick is to capture non-error codes, in my specific case 304 (Not modified). So the fallback assumes that if the status code is somehow unavailable, at least it's a non-erroneous one.

user_2191590

This is what I use for expanding WebClient functionality. StatusCode and StatusDescription will always contain the most recent response code/description.

                /// <summary>
                /// An expanded web client that allows certificate auth and 
                /// the retrieval of status' for successful requests
                /// </summary>
                public class WebClientCert : WebClient
                {
                    private X509Certificate2 _cert;
                    public WebClientCert(X509Certificate2 cert) : base() { _cert = cert; }
                    protected override WebRequest GetWebRequest(Uri address)
                    {
                        HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
                        if (_cert != null) { request.ClientCertificates.Add(_cert); }
                        return request;
                    }
                    protected override WebResponse GetWebResponse(WebRequest request)
                    {
                        WebResponse response = null;
                        response = base.GetWebResponse(request);
                        HttpWebResponse baseResponse = response as HttpWebResponse;
                        StatusCode = baseResponse.StatusCode;
                        StatusDescription = baseResponse.StatusDescription;
                        return response;
                    }
                    /// <summary>
                    /// The most recent response statusCode
                    /// </summary>
                    public HttpStatusCode StatusCode { get; set; }
                    /// <summary>
                    /// The most recent response statusDescription
                    /// </summary>
                    public string StatusDescription { get; set; }
                }

Thus you can do a post and get result via:

            byte[] response = null;
            using (WebClientCert client = new WebClientCert())
            {
                response = client.UploadValues(postUri, PostFields);
                HttpStatusCode code = client.StatusCode;
                string description = client.StatusDescription;
                //Use this information
            }
user_8814210
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