怎样用代码触发JComboBox的ItemEvent事情

[Yanbin_Q]

我的JComboBox，想像 Button.doClick()那样触发，代码应该是怎么写
我试图用
firePropertyChange()但不知道应该改变什么属性

对刚添加了一项的JComboBox用setSelectedIndex(0)方法也会出错

[mq612]

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

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

public class TestMain extends JFrame {
private MyComboBox box = null;

public TestMain() {
super("窗口");
JButton a = new JButton("触发按钮");
JPanel pane = new JPanel();
String [] arr = {"aaaaa", "bbbbb", "ccccc"};

box = new MyComboBox(arr);
box.setEditable(true);
pane.add(box);
pane.add(a);

box.addItemListener(new ItemListener(){
public void itemStateChanged(ItemEvent e) {
System.out.println(e.getItem());
}});

a.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
box.select(new ItemEvent(box, ItemEvent.ITEM_LAST, box.getSelectedItem(), ItemEvent.SELECTED));
}});

this.getContentPane().add(pane);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(300, 200);
this.setVisible(true);
}

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

}


class MyComboBox extends JComboBox{
public MyComboBox(Object [] o) {
super(o);
}
public void select(ItemEvent ie){
this.fireItemStateChanged(ie);
}
}

[Yanbin_Q]

也是个办法，为了使用JComboBox的受保护的fireItemStateChanged(ItemEvent)必须继承自JComboBox

[qybao]

可以不用继承，用反射就行了
for example
public void eventTest() {
try {
Class cls = JComboBox.class;
Method method = cls.getDeclaredMethod("fireItemStateChanged", new Class[]{ItemEvent.class});
method.setAccessible(true);
JComboBox cmb = new JComboBox(new String[]{"aa", "bb"});
ItemEvent event = new ItemEvent(cmb, 0, "aa", ItemEvent.SELECTED);
method.invoke(cmb, new Object[]{event}); //触发ItemEvent事件
} catch (Throwable e) {
e.printStackTrace();
}
}

[yuyu622]

顶了....