CODEWITHSUNDEEP
javaswingjcombobox
mhrzn
mhrzn

Reputation: 389

Java Refresh JCombobox

I created a JCombobox from sql data. And after i delete the item from combobox, the item still remain until i restart the application again?

I used additem method in a loop to add items to combobox , i have seen people used datamodel but i find this easy.'

code in mainfarme.java

public mainFrame()
    {
        initComponents();
       fillUserCombo();    
    }

public void fillUserCombo()
    {



    try {
       st=con.createStatement();
        rs=st.executeQuery("SELECT `username` FROM `users` WHERE 1");
        while(rs.next())
        {
       username=rs.getString(1);
       userCombo.addItem(username);
        }

    } 
    catch (SQLException ex) 
    {
    }
}



private void delUesrBtnActionPerformed(java.awt.event.ActionEvent evt) {                                           
            user u = new user();
            String user =userCombo.getSelectedItem().toString();
            u.delUser(user);
    }

code in user.java 

public void delUser(String user)
    {
        try
        {
             this.con=db.getCon();
          // System.out.println(user);
             String sql="DELETE FROM `users` where (username=?)";
             ps=(PreparedStatement)con.prepareStatement(sql);
             ps.setString(1,user);
             ps.execute();

             JOptionPane.showMessageDialog(null,"User Deleted");

             mainFrame mf = new mainFrame();
             mf.fillUserCombo();

             mf.revalidate();
             mf.repaint();
        } 
        catch (SQLException ex) 
        {
            Logger.getLogger(user.class.getName()).log(Level.SEVERE, null, ex);
        }

     }

here deluser deletes the user from the database after the delete button is pressed but after that the combobox item(username) are still there.

i try to call the fillusercombo method again thinking that it will refill the combofox but its the same ,also tried repaint() method.

How do i refresh the combobox? (PS. sorry for the poor style of coding ,still learning ?)

Upvotes: 2

Views: 1313

Answers (2)

mhrzn
mhrzn

Reputation: 389

I found the solution on another questions on stack overflow. I think did search there? before i asked anyway here it is 

private void delUesrBtnActionPerformed(java.awt.event.ActionEvent evt) {                                           
        user u = new user();
        String user =userCombo.getSelectedItem().toString();
        u.delUser(user);

        userCombo.removeAllItems();
        fillUserCombo();


}

The link to the solution

i remove the all the items using removeAllItems() and again call the fillUserCombo ().

camickr also did mentioned that before but i wan't quite sure how to do that.

Upvotes: 0

camickr
camickr

Reputation: 324197

mainFrame mf = new mainFrame();
mf.fillUserCombo();

Don't create a new mainframe() object. This object is just sitting in memory because you don't appear to be doing anything with it.

i have seen people used datamodel but i find this easy.

You have seen this code because it is the proper way to solve the problem. All you need is a reference to the model. Then you remove all the items and add the new items to the model. Or you create a new model and add the model to the combo box.

There is absolutely no good reason to create an entire new frame just to reload data!!!

Upvotes: 4

Related Questions