private void Propreties_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var PropCombo = (ComboBox)sender;
            String spec = PropCombo.SelectedValue as String;
            if (spec == null) spec = "";
            Faculty FacultyDialog;
            bool? FacultyDialogResult = false;

            // If this spec already choosen
            foreach(Specialization Spec in Specs)
            {
                if(Spec != null && Spec.Spec.Equals(spec))
                {
                    MessageBox.Show("Одну и ту же специальность нельзя выбирать дважды", "Предупреждение", MessageBoxButton.OK, MessageBoxImage.Warning);
                    PropCombo.SelectedItem = null;
                    return;
                }
            }

            // If something choosen, select facs
            if (spec.Equals(""))
                return;
            else
            {
                FacultyDialog = new Faculty(spec);
                FacultyDialogResult = FacultyDialog.ShowDialog();
            }
            if ((bool)FacultyDialogResult)
            {
                if (PropCombo.Name.Equals("ControlFirstPriority"))
                    Specs[0] = new Specialization(spec, FacultyDialog.Output);
                else if (PropCombo.Name.Equals("ControlSecondPriority"))
                    Specs[1] = new Specialization(spec, FacultyDialog.Output);
                else if (PropCombo.Name.Equals("ControlThirdPriority"))
                    Specs[2] = new Specialization(spec, FacultyDialog.Output);
            }
            else
                PropCombo.SelectedItem = null;
        }
        private void ControlMagistrSpec_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var PropCombo = (ComboBox)sender;
            String spec = PropCombo.SelectedValue as String;
            Faculty FacultyDialog;

            // If something choosen, select facs
            if (spec.Equals(""))
                return;
            else
            {
                FacultyDialog = new Faculty(spec);
                FacultyDialog.ShowDialog();
            }
            if (PropCombo.Name.Equals("ControlMagistrSpec"))
            {
                Specs[0] = new Specialization(spec, FacultyDialog.Output);
                Specs[1] = null;
                Specs[2] = null;
            }
        }
        private void Propreties_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var PropCombo = (ComboBox)sender;
            String spec = PropCombo.SelectedValue as String;

            // If something choosen, select facs
            if (spec.Equals(""))
                return;
            else
            {
                Faculty FacultyDialog = new Faculty(spec);
                FacultyDialog.ShowDialog();
            }
            if (PropCombo.Name.Equals("ControlFirstPriority"))
            {

            }
            else if (PropCombo.Name.Equals("ControlSecondPriority"))
            {

            }
            else if (PropCombo.Name.Equals("ControlThirdPriority"))
            {

            }
        }