如何在netbeans中打開JDialog表單？

Question

我已經構建了Swing GUI的類JDialog form(diglog_promotion)和一個按鈕。我想JDialog形式表現，當我點擊按鈕，所以我編寫

dialog_promotion f = new dialog_promotion();     
f.setVisible(true); 

我點擊按鈕後，它拋出一個錯誤：

尚未

支持，我試着使用它與eclipe它工作
我錯了什麼？

Answer 1

Inside of your method Actionperformed for any particular case you want call JoptionPane.showMessageDialog(,); with the message you want. I have tried this in netbeans it works. 
private void btnSaveActionPerformed(java.awt.event.ActionEvent evt) 
{ 
... 
... 
if(saveisclicked) 
{ 
    System.out.println("Please Fill user name"); 
    JOptionPane.showMessageDialog(null, "Please Enter User Name field"); 

} 
... 
...