C# HttpClient Put/Post Google Calendar API

Question

I am trying to perform a PUT to Google Calendar API v3 in order to add an attendee, but every time I get the response 400 BAD REQUEST. I have simplified it to just attempt to update the max number of attendees to see if it will take, but no dice...

        public void AddAttendeeToEvent(string calendarId, string eventId, string attendeeEmail)
        {
        try
        {
            var httpClient = new HttpClient();
            httpClient.DefaultRequestHeaders.Add("Authorization", "Bearer " + AuthenticationHelper.Instance.Token);

            var baseUrl = String.Format("https://www.googleapis.com/calendar/v3/calendars/{0}/events/{1}", calendarId, eventId);
            //var postData = string.Format ("attendees[].email={0}", attendeeEmail);
            var postData = "maxAttendees=100";
            var content = new StringContent(postData, Encoding.UTF8, "application/x-www-form-urlencoded");

            var response = httpClient.PutAsync(baseUrl, content).Result;
            response.EnsureSuccessStatusCode ();
        }
        catch(Exception ex)
        {
            string s = "";
        }
    }

Note - This is in Xamarin, there is no client library available. Has to be done manually for now...and the documentation on this is horrible.

Answer 1

I propose you drop this code and start over using C# Calendar API client library. You can get it from the downloads in the documentation page: https://developers.google.com/google-apps/calendar/

However, as the first step, please read the getting started guidelines and obtain a correct Oauth2 token.