public CheckAbsent(ObservableCollection <Employee> listEmployeeFromMainWindows, ObservableCollection <DayCheckedInfo> daysCheckedFromMainWindows)
        {
            InitializeComponent();
            daysChecked          = daysCheckedFromMainWindows;
            defaultListEmployees = new ObservableCollection <Employee>();
            defaultListEmployees = listEmployeeFromMainWindows;

            if (daysCheckedFromMainWindows.Count == 0)
            {
                DayCheckedInfo infoDataToday = new DayCheckedInfo();
                foreach (Employee e in listEmployeeFromMainWindows)
                {
                    InfoCheckEmployee temp = new InfoCheckEmployee();
                    temp.Id       = e.Id;
                    temp.Name     = e.Name;
                    temp.Position = e.Position;
                    infoDataToday.infoEmployees.Add(temp);
                }
                daysCheckedFromMainWindows.Add(infoDataToday);
                infoDataToday.dayChecked = DateTime.Today;
                employeeList.ItemsSource = daysCheckedFromMainWindows.Last().infoEmployees;
            }
            else
            {
                for (int i = 0; i < daysCheckedFromMainWindows.Count; i++)
                {
                    if (daysCheckedFromMainWindows[i].dayChecked == DateTime.Today)
                    {
                        employeeList.ItemsSource = daysCheckedFromMainWindows[i].infoEmployees;
                    }
                }
            }
            checkCalendar.SelectedDate = DateTime.Today;
        }
        private void checkCalendar_SelectedDatesChanged(object sender, SelectionChangedEventArgs e)
        {
            bool hasChangedList = false;

            for (int i = 0; i < daysChecked.Count; i++)
            {
                if (daysChecked[i].dayChecked == checkCalendar.SelectedDate)
                {
                    hasChangedList = true;
                }
            }

            if (!hasChangedList)
            {
                DayCheckedInfo infoDataNew = new DayCheckedInfo();

                foreach (Employee employeeTempNew in defaultListEmployees)
                {
                    InfoCheckEmployee temp = new InfoCheckEmployee();
                    temp.Id       = employeeTempNew.Id;
                    temp.Name     = employeeTempNew.Name;
                    temp.Position = employeeTempNew.Position;
                    infoDataNew.infoEmployees.Add(temp);
                }
                infoDataNew.dayChecked = (DateTime)checkCalendar.SelectedDate;
                daysChecked.Add(infoDataNew);
                employeeList.ItemsSource = daysChecked.Last().infoEmployees;
            }
            else
            {
                for (int i = 0; i < daysChecked.Count; i++)
                {
                    if (checkCalendar.SelectedDate == daysChecked[i].dayChecked)
                    {
                        employeeList.ItemsSource = daysChecked[i].infoEmployees;
                    }
                }
            }
        }