Facebook.FacebookOAuthClient.BuildExchangeCodeForAccessTokenResult C# (CSharp) Method

        private object BuildExchangeCodeForAccessTokenResult(string json)
        {
            var returnParameter = new JsonObject();
            FacebookUtils.ParseQueryParametersToDictionary("?" + json, returnParameter);

            // access_token=string&expires=long or access_token=string
            // Convert to JsonObject to support dynamic and be consistent with the rest of the library.
            var jsonObject = new JsonObject();
            jsonObject["access_token"] = returnParameter["access_token"];

            // check if expires exist coz for offline_access it is not present.
            if (returnParameter.ContainsKey("expires"))
            {
                jsonObject.Add("expires", Convert.ToInt64(returnParameter["expires"]));
            }

            return jsonObject;
        }