public AddOrEditTestViewModel(PageService pageService, TestsRestClient testsClient)
        {
            _pageService = pageService;

            _testsClient = testsClient;

            if (!IsAdding)
            {
                if (TestId != null)
                {
                    var test = HttpResponseMessageConverter.GetResult <dynamic>(_testsClient.GetTestById((int)TestId));

                    Duration = test.duration;
                    MaximumNumberOfQuestions = test.maximumNumberOfQuestions;

                    Name        = test.name;
                    Description = test.description;

                    StartDate      = test.startDate;
                    StartTime      = test.startDate;
                    ExpirationDate = test.expirationDate;
                    ExpirationTime = test.expirationDate;
                }
            }
        }
        public PassingTheTestViewModel(PageService pageService, UserService userService, TestsRestClient testsClient, AnswersRestClient answersClient, StudentsRestClient studentsClient, QuestionsRestClient questionsClient, StudentAnswersRestClient studentAnswersClient)
        {
            _pageService = pageService;
            _userService = userService;

            _testsClient          = testsClient;
            _answersClient        = answersClient;
            _studentsClient       = studentsClient;
            _questionsClient      = questionsClient;
            _studentAnswersClient = studentAnswersClient;

            if (TestId != null)
            {
                Test = HttpResponseMessageConverter.GetResult <dynamic>(_testsClient.GetTestById((int)TestId));

                InitTimer();
                FormQuestions();

                ActiveQuestion = Questions[0];

                Answers.Clear();
                Answers = new ObservableCollection <dynamic>(HttpResponseMessageConverter.GetResult <List <dynamic> >(_answersClient.GetAnswersByQuestionId(Convert.ToInt32(ActiveQuestion.id))));
            }
        }