C# HttpWebRequest POST => !! Unexpected error while processing request: invalid %-encoding
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i am facing a problem where i try to communicate with a Ruby API from a C# application.

I need to POST some JSON data, with the parameter name "data" but the API return me: '!! Unexpected error while processing request: invalid %-encoding'.

I tried with Content-Type set to 'application/json' and 'application/x-www-form-urlencoded; charset=utf-8'.

My POST data look like this 'data=some_json_string'.

I figure i should escape the json string, so if it is my problem, how to do it with .NET without using a 3rd party library?

Code:

            byte[] data = System.Text.ASCIIEncoding.UTF8.GetBytes(sdata);

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(new Uri(url, UriKind.Absolute));

            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded; charset=utf-8";
            request.ContentLength = data.Length;

            Stream reqStream = request.GetRequestStream();

            // Send the data.
            reqStream.Write(data, 0, data.Length);
            reqStream.Close();

Thanks in advance!