Model-View, where to start?

[soul_rebel]

I have a large Number of items that should each be represented by an Item in a Tree.
I used QTreeWidget up until now, but have to / want to use a Model-View-Thing instead.

Where do I start? As far as I understood I shouldnt need to reimplement QTreeView, only the QstandardItemModel, or is it sufficient to keep QStandardItemModel and just subclass QStandardItem?

For a better understanding I'll try to describe my situation in more detail:
I have a QList <QMyObject*> of about 18K Objects. Each of those is currently represented by one

class QMyListItem : public QObject, public QTreeWidgetItem

class QMyListItem : public QObject, public QTreeWidgetItem

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These Items contain some Members (i.e. a Pointer to the QMyObject they represent) and need to be Qobjects to stay "informed" about updates in their QMyObjects (through Signals'n'Slots).
The TreeWidget has 3 columns, the contents is set by the QMyListItems themself.

The QMyListItems are sorted into about 70 categories (simple QTreeWidgetItems).

How would I achieve similar behaviour with a custom "Model-View-Thing"?

Thank you for your help!