public MainWindow()
        {
            loginWindow = new LoginWindow();
            loginWindow.ShowDialog();
            InitializeComponent();
            switch (loginWindow.Role)
            {
            case "Doctor":
                DoctorTabControl.Visibility  = Visibility.Visible;
                PatientTabControl.Visibility = Visibility.Hidden;
                sQLite = new SQLiteFunctions(PatientListView);
                OutputInformationAboutDoctor(loginWindow.Doctor, true);
                sQLite.SelectPatients(loginWindow.Doctor.FIO);
                break;

            case "Patient":
                DoctorTabControl.Visibility  = Visibility.Hidden;
                PatientTabControl.Visibility = Visibility.Visible;
                sQLite = new SQLiteFunctions(DoctorsListView);
                OutputInformationAboutPatient(loginWindow.Patient.FIO, loginWindow.Patient.Age, loginWindow.Patient.Gender);
                sQLite.SelectDoctors();
                break;

            case "Admin":
                //Admin = sQLite.ReturnAdmin(sQLite.CheckFIO);
                break;
            }
        }
 public LoginWindow()
 {
     InitializeComponent();
     sQLite = new SQLiteFunctions();
 }