private void btnUDeleteActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btnUDeleteActionPerformed
        // TODO add your handling code here:
        String id = tbxUUserID.getText().trim().replace("'", "");
        if (id.equals(""))
        {
            tbxError.setText("Empty user ID.");
            return ;
        }
        if (id.equals("admin"))
        {
            tbxError.setText("This use can't be deleted.");
            return;
        }
        String msg = "You are about to delete user '"+id+"'. \r\nDo you wish to continue?";
        int x = JOptionPane.showConfirmDialog(this, msg, "Do you wish to continue?",JOptionPane.YES_NO_OPTION);
        if (x!=0)
            return;
        User_Controller UC = new User_Controller("localhost", DBName, DBAccount, DBPwd);
        
        boolean flag = UC.DeleteUser(id);
        if(!flag)
        {
            tbxError.setText(UC.err);
            return;
        }
        ReturnedUsers = new ArrayList();
        ShowUsers();
        tbxError.setText("User '" + id +"' is deleted successfully.");
    }