public void Load()
        {
            Classes.Clear();
            if (SelectedTeacher != null)
            {
                foreach (ClassViewModel _class in MainViewModel.Instance.Parameters.Classes.Where(c => c.Teachers.Contains(SelectedTeacher)))
                {
                    EntryClassViewModel entryClass = new EntryClassViewModel()
                    {
                        Class = _class
                    };
                    foreach (StudentViewModel student in _class.Students)
                    {
                        EntryStudentViewModel entryStudent = new EntryStudentViewModel()
                        {
                            Student = student
                        };
                        entryStudent.LoadEntryTrimesterSubjectComments(SelectedTeacher);
                        entryClass.Students.Add(entryStudent);
                    }
                    Classes.Add(entryClass);
                }

                SelectedClass = Classes.FirstOrDefault();
                if (SelectedClass != null)
                {
                    SelectedClass.SelectedStudent = SelectedClass.Students.FirstOrDefault();
                    if (SelectedClass.SelectedStudent != null)
                    {
                        SelectedClass.SelectedStudent.SelectedTrimesterSubjectCommentsSubject = SelectedClass.SelectedStudent.TrimesterSubjectCommentsSubjects.FirstOrDefault();
                    }
                }
            }
        }
        public void Load()
        {
            Classes.Clear();
            foreach (ClassViewModel _class in MainViewModel.Instance.Parameters.Classes)
            {
                EntryClassViewModel entryClass = new EntryClassViewModel()
                {
                    Class = _class
                };
                foreach (StudentViewModel student in _class.Students)
                {
                    EntryStudentViewModel entryStudent = new EntryStudentViewModel()
                    {
                        Student = student
                    };
                    entryClass.Students.Add(entryStudent);
                }
                Classes.Add(entryClass);
            }

            SelectedClass = Classes.FirstOrDefault();
            if (SelectedClass != null)
            {
                SelectedClass.SelectedStudent = SelectedClass.Students.FirstOrDefault();
            }
        }
        private static void SelectedStudentChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            EntryClassViewModel entryClass = (EntryClassViewModel)d;

            entryClass.SelectedStudentChangedEvent?.Invoke();
        }