如何判断在CheckComboBox中选择了多少项？

import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.CheckComboBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class CheckComboBoxExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        CheckComboBox<String> checkComboBox = new CheckComboBox<>();
        checkComboBox.getItems().addAll("Item 1", "Item 2", "Item 3", "Item 4", "Item 5");

        VBox root = new VBox(checkComboBox);
        Scene scene = new Scene(root, 200, 200);
        primaryStage.setScene(scene);
        primaryStage.show();

        checkComboBox.getCheckModel().getCheckedItems().addListener((ObservableList<? extends String> c) -> {
            int selectedCount = c.size();
            System.out.println("Selected count: " + selectedCount);
        });
    }

    public static void main(String[] args) {
        launch(args);
    }
}