private void RefreshGroups()
        {
            observableGroupList.Clear();
            if (!(selectedFaculty is null))
            {
                selectedFaculty.Sort();

                foreach (var group in selectedFaculty)
                {
                    observableGroupList.Add(group);
                }

                if (observableGroupList.Count != 0)
                {
                    selectedGroup = selectedFaculty.Get(0);
                }
            }
        }
        public void Refresh()
        {
            observableStudentList.Clear();
            currentList.Sort();

            foreach (var student in currentList)
            {
                observableStudentList.Add(student);
            }

            if (observableStudentList.Count != 0)
            {
                SelectedStudent = currentList.Get(0);
                Resources["UserInfoVisibility"] = Visibility.Visible;
                Resources["BannerVisibility"]   = Visibility.Hidden;
                Resources["EditButtonsEnabled"] = true;
            }
            else
            {
                Resources["UserInfoVisibility"] = Visibility.Hidden;
                Resources["BannerVisibility"]   = Visibility.Visible;
                Resources["EditButtonsEnabled"] = false;
            }
        }