connect(choiceWidget, SIGNAL(clicked()), mainWidget, SLOT(reg_prepare()));

QObject::connect(&choiceWidget, SIGNAL(clicked()), &mainWidget, SLOT(reg_prepare()));

public slots:
    void reg_prepare();

#include <QtGui/QApplication>
#include "choicewidget.h"
#include "mainwidget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWidget mainWidget;
    ChoiceWidget choiceWidget;
        choiceWidget.show();    
        return a.exec();
}

connect(button, SIGNAL(clicked()), mainWidget, SLOT(reg_prepare()));

#include <QtGui/QApplication>
#include "choicewidget.h"
#include "mainwidget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWidget mainWidget;
    ChoiceWidget choiceWidget;
        QObject::connect(&choiceWidget->Кнопка, SIGNAL(clicked()), &mainWidget, SLOT(reg_prepare()));
        choiceWidget.show();    
        return a.exec();
}

#include "mainwidget.h"

MainWidget::MainWidget()
{
...
}

void MainWidget::reg_prepare(){
...
}

#include "choicewidget.h"
#include "mainwidget.h"

ChoiceWidget::ChoiceWidget(QWidget *parent)
    : QWidget(parent)
{
...
}

#ifndef CHOICEWIDGET_H
#define CHOICEWIDGET_H

#include <QtGui/QWidget>
#include <QPushButton>
#include <QVBoxLayout>


class ChoiceWidget : public QWidget
{
    Q_OBJECT

public:
    ChoiceWidget(QWidget *parent = 0);
    ~ChoiceWidget();

private:
    QWidget *choiceWidget;
    QPushButton *reg;
    QPushButton *del;
    QVBoxLayout *layout;
};

#endif // CHOICEWIDGET_H

#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QGridLayout>

class MainWidget : public QWidget
{
public:
    MainWidget();

public slots:
    void reg_prepare();
    void del_prepare();

Цитата(Гость @ 13.10.2011, 10:35)

connect(button, SIGNAL(clicked()), mainWidget, SLOT(reg_prepare()));

connect(button, SIGNAL(clicked()), this, SLOT(reg_prepare()));