public MainWindow() { const int numberOfStrings = 100; InitializeComponent(); List <String> eventsList = EventOptions.getEvents(); UIEventPicker.SetBinding(ComboBox.ItemsSourceProperty, new Binding() { Source = eventsList }); UIGenerate.Click += (o, a) => { var comboBoxValue = UIEventPicker.SelectedItem; String[] stringsToPrint = new String[numberOfStrings]; Diagnose diagnose = new Diagnose(); Register register = new Register(); if (comboBoxValue != null) { switch (comboBoxValue.ToString()) { case "Register": stringsToPrint = register.StringsToPrint(100); break; case "Diagnose": stringsToPrint = diagnose.StringsToPrint(100); break; default: break; } AllStrings.ItemsSource = stringsToPrint; } }; UIClear.Click += (o, a) => { AllStrings.ItemsSource = null; }; }