TSVCEO.CloudPrint.Util.OAuthTicket.RefreshAuthToken C# (CSharp) Method

        protected void RefreshAuthToken()
        {
            lock (AccessTokenLock)
            {
                if (AccessTokenExpires < DateTime.Now)
                {
                    var req = HTTPHelper.CreateRequest(null, OAuthTokenRequestUri);
                    var reqdata = new
                    {
                        refresh_token = RefreshToken,
                        client_id = ClientId,
                        client_secret = ClientSecret,
                        grant_type = "refresh_token"
                    };

                    var respdata = HTTPHelper.ToJson(HTTPHelper.SendUrlEncodedPostData(req, reqdata));

                    _AccessToken = respdata.access_token;
                    _TokenType = respdata.token_type;
                    AccessTokenExpires = DateTime.Now.Add(new TimeSpan((respdata.expires_in - 60) * 10000000));
                }
            }
        }