private void OnAllTeachersBtnClick(object sender, RoutedEventArgs e)
        {
            this.ExcelGrid.Visibility = Visibility.Hidden;
            PersonsListWindow teachersWindow = new PersonsListWindow(this);

            teachersWindow.lbltextApplicantList.Content = "Teachers";
            teachersWindow.TeacherComboBox.IsEnabled    = false;
            HelperMethodes.UpdateGrid(MainGrid, MainFormColRight, teachersWindow, 70);
            this.logoMicrosoft.Visibility = Visibility.Visible;
        }
        private async void OnAllStudentBtnClick(object sender, RoutedEventArgs e)
        {
            this.ExcelGrid.Visibility = Visibility.Hidden;
            StudentListWindow StudentsWindow = new StudentListWindow(this);

            HelperMethodes.UpdateGrid(MainGrid, MainFormColRight, StudentsWindow, 70);
            this.logoMicrosoft.Visibility = Visibility.Visible;
            StudentController stctrl = new StudentController();

            StudentsWindow.studentList.ItemsSource = await stctrl.GetAllAsync();
        }
        private async void OnApplicantBtnClick(object sender, RoutedEventArgs e)
        {
            PersonsListWindow AplicantsWindow = new PersonsListWindow(this);

            this.ExcelGrid.Visibility = Visibility.Visible;
            AplicantsWindow.lbltextApplicantList.Content = "Applicants";
            AplicantsWindow.TeacherComboBox.IsEnabled    = false;
            this.logoMicrosoft.Visibility = Visibility.Visible;
            HelperMethodes.UpdateGrid(MainGrid, MainFormColRight, AplicantsWindow, 70);
            ApplicantController appcontrol = new ApplicantController();

            AplicantsWindow.ApplList.ItemsSource = await appcontrol.GetAllAsync();
        }
        private void OnApplicantBtnClickAdd(object sender, RoutedEventArgs e)
        {
            AddEntityWindow AddWindow = new AddEntityWindow();

            HelperMethodes.UpdateGrid(this.MainGrid, this.MainFormColRight, AddWindow, 100);
        }