Qt信号槽传参没反应

两个窗口传参时，必须在mainwindow中显示窗口，都在同一主界面下才能使用信号槽传参数，原因待查
eg: connect(ui->action_db,SIGNAL(triggered()), this, SLOT(databseshow()));
connect(obj,SIGNAL(connectmysql(QString,int,QString,QString,QString)),this,
SLOT(doprocessDbconnect(QString,int,QString,QString,QString)),Qt::QueuedConnection);