public UserControlBooks(FormMain form1)
 {
     InitializeComponent();
     form1.LeaveBooksTab += Form1_LeaveTabPage;
     form1.EnterBooksTab += Form1_EnterBooksTab;
 }
 public UserControlPublishers(FormMain form)
 {
     InitializeComponent();
     form.EnterPublishersTab += Form_EnterPublishersTab;
 }
 public UserControlOrders(FormMain form1)
 {
     InitializeComponent();
     form1.LeaveOrdersTab += Form1_LeaveOrdersTab;
     form1.EnterOrdersTab += Form1_EnterOrdersTab;
 }
 public UserControlEmployees(FormMain form)
 {
     InitializeComponent();
     form.EnterEmployeesTab += Form_EnterEmployeesTab;
 }