private void btnBooks_Click(object sender, RoutedEventArgs e)
{
MainWin mainWin = new MainWin(userData);
this.Hide();
mainWin.ShowDialog();
this.Show();
}
private void btnAddBookInList_Click(object sender, RoutedEventArgs e)// добавление книги в лист
{
MainWin mainWin = new MainWin(CurrentUser, SelectReader);
this.Opacity = 0.5;
mainWin.ShowDialog();
this.Opacity = 1;
lvAddBook.ItemsSource = HelpClass.HelpData.AddedInSessionBooks.ToList();
}