public void Initialize()
 {
     if (_printerUserInterface == null)
     {
         _printerUserInterface = new SimulatedFiscalPrinterForm();
         _printerUserInterface.Show();
         _printerUserInterface.FormClosed += new System.Windows.Forms.FormClosedEventHandler(_printerUserInterface_FormClosed);
     }
 }
 void _printerUserInterface_FormClosed(object sender, System.Windows.Forms.FormClosedEventArgs e)
 {
     _printerUserInterface.FormClosed -= new System.Windows.Forms.FormClosedEventHandler(_printerUserInterface_FormClosed);
     _printerUserInterface             = null;
 }