Qt 对话框显示控制按钮

在对话框窗体构造函数加入

SystemDialog::SystemDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::SystemDialog)
{
    ui->setupUi(this);

    Qt::WindowFlags flags=Qt::Dialog;

    flags |=Qt::WindowMinimizeButtonHint;
    flags |=Qt::WindowMaximizeButtonHint;
    flags |=Qt::WindowCloseButtonHint;
    setWindowFlags(flags);

}