데이터베이스에서 값을 가져온 후 jComboBox를 지우는 방법

Question

누구든지이 코드를 사용하여 나를 도와 줄 수 있습니까?

1 private void jComboBox3ActionPerformed(java.awt.event.ActionEvent evt) { 
2 Connection con; 
3 Statement stmt; 
4 try { 
5   
6  Class.forName("sun.jdbc.odbc.JdbcOdbc"); 
7 } catch (ClassNotFoundException ex) { 
8  JOptionPane.showMessageDialog(null, ex); 
9 } 
10 try { 
11  con= DriverManager.getConnection("Jdbc:Odbc:food"); 
12  stmt= con.createStatement(); 
13  String sql="select i_name from food where category= '"+ jComboBox3.getSelectedItem().toString()+"'"; 
14  ResultSet RS= stmt.executeQuery(sql); 
15  JcbSub.setSelectedItem(""); 
16  while(RS.next()){ 
17    
18   JcbSub.addItem(RS.getString("i_name")); 
19    
20    
21  } 
22   
23  
24   
25 } catch (SQLException ex) { 
26  Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex); 
27 } 
28  
29  
30 
31 } 

Answer 1

것은이

private void jComboBox3ActionPerformed(java.awt.event.ActionEvent evt) { 
    Connection con; 
    Statement stmt; 
try { 

    Class.forName("sun.jdbc.odbc.JdbcOdbc"); 
} catch (ClassNotFoundException ex) { 
    JOptionPane.showMessageDialog(null, ex); 
} 
    //add this to remove all Items 
    JcbSub.removeAllItems(); 
if(jComboBox3.getSelectedItem() == 0) { 
    try { 


    con= DriverManager.getConnection("Jdbc:Odbc:food"); 
    stmt= con.createStatement(); 
    String sql="select i_name from food where category= '"+jComboBox3.getSelectedItem().toString()+"'"; 
    ResultSet RS= stmt.executeQuery(sql); 
    JcbSub.setSelectedItem(""); 
    while(RS.next()){ 

     JcbSub.addItem(RS.getString("i_name")); 


    } 



} catch (SQLException ex) { 
    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex); 
} 

}else if(jComboBox3.getSelectedItem() == 1) { 
//etc... 
} 
// or use Switch case  

} 

처럼 할 필요가 :

내가 다른 값이 코드에서 jComboBox3에서 선택했을 때 어떻게 JcbSub (JComboBox에)를 취소하도록 요청하고 싶어 여기에 코드를 입력