#ifndef TREEDBVIEW_H
#define TREEDBVIEW_H
#include <QAbstractItemView>
#include <QAbstractItemModel>
#include <QWidget>
class TreeDBItem;
class TreeDBModel;
class TreeDBView : public QAbstractItemView
{
    Q_OBJECT
public:
    explicit TreeDBView(QWidget *parent = Q_NULLPTR);
    ~TreeDBView();
    void setModel(QAbstractItemModel *dbmodel) const override;
};
#endif // TREEDBVIEW_H

// Текст treedbview.cpp (отрывок)
#include "treedbitem.h"
#include "treedbmodel.h"
#include "treedbview.h"
TreeDBView::TreeDBView(QWidget *parent) : QAbstractItemView (QWidget *parent = Q_NULLPTR)
{
    Q_D(TreeDBView);
    d->initialize();
}
TreeDBView::~TreeDBView()
{
}
void TreeDBView::setModel(QAbstractItemModel *dbmodel) const
{
....
}