How to create a drop-down list box ComboBox control?

Most graphical user interface (GUI) toolkits and frameworks, such as Java Swing, JavaFX, and Windows Forms, offer methods for creating a ComboBox control. Using Java Swing as an example, below is a guide on how to create a ComboBox control.

1. Import the necessary packages.

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;

1. Create a JFrame window.

JFrame frame = new JFrame("ComboBox Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

1. Create a JPanel panel and add a ComboBox control to it.

JPanel panel = new JPanel();
String[] options = {"Option 1", "Option 2", "Option 3", "Option 4"};
JComboBox<String> comboBox = new JComboBox<>(options);
panel.add(comboBox);

1. Add the panel to the window and make the window visible.

frame.add(panel);
frame.pack();
frame.setVisible(true);

By following the steps above, you can create a simple ComboBox control in a Java Swing application. You can further customize and manipulate the ComboBox control as needed, such as styling, layout, and event handling.