连接槽位错误

我有文件program .cpp控制我所有的连接页面，但当我想从另一个类连接一个program .cpp函数到其他按钮时，我给出了一个错误

这是代码:

QObject::connect(LoginPage->Buttons->button(QDialogButtonBox::Ok),SIGNAL(clicked()),this,SLOT(check_user()));

，这是错误:

/home/alireza/Documents/qt/alireza/program .cpp:19:错误:没有匹配函数调用'QObject::connect(QPushButton*， const char*， programm* const, const char*)'

,这是一个完全注释的函数声明:

void programm::check_user()
{
/*QString user = LoginPage->EditPassWord->displayText();
QString password = LoginPage->ComboUsername->currentText();
QSqlQuery myquery("SELECT Username FROM TeacherUsers");
while(myquery.next())
{
    QString Username = MyDB->query->value(0).toString();
    QString pass = MyDB->query->value(1).toString();
    qDebug()<<Username << "   " << pass ;
    //if (Username == user)
}*/
}

programm.h:

#ifndef PROGRAMM_H
#define PROGRAMM_H
#include "login.h"
#include "mainwindow.h" 
#include "nazem.h"
#include "database.h"
#include <QtGui>
#include <QtCore> 
#include <QObject>
class programm
{
Q_OBJECT
public:
    programm();
    Login *LoginPage;
    MainWindow *MainWindowPage;
    nazem *nazm;
    database *MyDB;
public slots :
    void check_user();
};
#endif // PROGRAMM_H