button1->setProperty("value", 1)的用法

class  Dialog :  public  QDialog
{
...
public :
    // 构造函数
    Dialog(QWidget *parent = 0)
    {
        ...

        // 设置扩展属性
        ui->button1->setProperty( "value" , 1);
        ui->button2->setProperty( "value" , 2);
        ui->button3->setProperty( "value" , 3);
        ui->button4->setProperty( "value" , 4);

        // 连接信号和槽
        connect(ui->button1, SIGNAL(clicked()),  this , SLOT(accept()));
        connect(ui->button2, SIGNAL(clicked()),  this , SLOT(accept()));
        connect(ui->button3, SIGNAL(clicked()),  this , SLOT(accept()));
        connect(ui->button4, SIGNAL(clicked()),  this , SLOT(accept()));
    }

    // 重载槽
    void  accept()
    {
        // 获取信号发送者
        QPushButton *button = qobject_cast(sender());

        // 设置返回值
        if  (button)
        {
            m_value = button->property( "value" ).toInt();
        }

        // 向下传递
        QDialog::accept();
    }

    // 获取返回值
    int  value()  const
    {
        return  m_value;
    }

private :
    int  m_value;
...
};