Question

I am new to Windows Phone 7 application development. I am trying to call a URL in my program using POST method which takes some parameters. After the successful post I am supposed to get the response in JSON format. But I am not getting the response. The code I am using is:

    public void Submit()
    {
        // Prepare web request...
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(new Uri(someUrl, UriKind.Absolute));
        myRequest.Method = "POST";
        myRequest.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);

        myRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), myRequest);
    }


    public string url { get; set; }
    private Dictionary<string, string> _parameters = new Dictionary<string, string>();

    public Dictionary<string, string> parameters
    {
        get { return _parameters; }
        set { _parameters = value; }
    }

    string boundary = "----------" + DateTime.Now.Ticks.ToString();


    private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        Stream postStream = request.EndGetRequestStream(asynchronousResult);
        parameters.Add("userid", "0");
        parameters.Add("locationid", "0");
        writeMultipartObject(postStream, parameters);
        postStream.Close();

        request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);
    }

    private void GetResponseCallback(IAsyncResult asynchronousResult)
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
        Stream streamResponse = response.GetResponseStream();
        StreamReader streamRead = new StreamReader(streamResponse);
        streamResponse.Close();
        streamRead.Close();
        // Release the HttpWebResponse
        response.Close();
    }

    public void writeMultipartObject(Stream stream, object data)
    {
        StreamWriter writer = new StreamWriter(stream);
        if (data != null)
        {
            foreach (var entry in data as Dictionary<string, string>)
            {
                WriteEntry(writer, entry.Key, entry.Value);
            }
        }
        writer.Write("--");
        writer.Write(boundary);
        writer.WriteLine("--");
        writer.Flush();
    }

    private void WriteEntry(StreamWriter writer, string key, object value)
    {
        if (value != null)
        {
            writer.Write("--");
            writer.WriteLine(boundary);
            if (value is byte[])
            {
                byte[] ba = value as byte[];

                writer.WriteLine(@"Content-Disposition: form-data; name=""{0}""; filename=""{1}""", key, "sentPhoto.jpg");
                writer.WriteLine(@"Content-Type: application/octet-stream");
                //writer.WriteLine(@"Content-Type: image / jpeg");
                writer.WriteLine(@"Content-Length: " + ba.Length);
                writer.WriteLine();
                writer.Flush();
                Stream output = writer.BaseStream;

                output.Write(ba, 0, ba.Length);
                output.Flush();
                writer.WriteLine();
            }
            else
            {
                writer.WriteLine(@"Content-Disposition: form-data; name=""{0}""", key);
                writer.WriteLine();
                writer.WriteLine(value.ToString());
            }
        }
    }

I cannot find what the real problem is. Anybody out there to help me out?

Answer 1

I got the solution as:

   {
        Dictionary<string, object> param = new Dictionary<string, object>();
        param.Add(DataHolder.USER_ID, "0");
        param.Add(DataHolder.DEFAULT_LOCATION_ID, "0");
        PostClient proxy = new PostClient(param);
        proxy.DownloadStringCompleted += new PostClient.DownloadStringCompletedHandler(proxy_DownloadStringCompleted);           
        proxy.DownloadStringAsync(new Uri(DataHolder.mainConfigFetchUrl, UriKind.Absolute));





    }

    void proxy_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
    {
        if (e.Error == null)
        {
            //Process the result... 
            string data = e.Result;
        }
    }

For PostClient we will need a WindowsPhonePostClient.dll which can be obtained from http://postclient.codeplex.com/