private void AddButton_Click(object sender, RoutedEventArgs e)
        {
            Window addNewEmployeeWindow = new EmployeesAdd();

            addNewEmployeeWindow.ShowDialog();

            Refresh();
        }
        private void EditButton_Click(object sender, RoutedEventArgs e)
        {
            var employeeDTO = AllEmployeesList.SelectedItem as EmployeeDTO;

            if (employeeDTO != null)
            {
                Window addNewEmployeeWindow = new EmployeesAdd(employeeDTO.ID);
                addNewEmployeeWindow.ShowDialog();
            }
        }