private void BtnSearchChild_Click(object sender, RoutedEventArgs e)
{
ListViewStaff1.Visibility = Visibility.Visible;
btnEmptySearch.Visibility = Visibility.Visible;
children = DbOperations.GetChildren(txtNameChild.Text);
txtNameChild.Clear();
foreach (var c in children)
{
c.UpdateLeaveAlone();
}
ListViewStaff1.ItemsSource = children;
}