@Sam
Thanks you :)
Why can't i set using? can't we do it for tableview? is it only for widgets?
tableView->setIndexWidget(index,comboDelegate);
'QAbstractItemView::setIndexWidget' : cannot convert parameter 2 from 'ComboBoxDelegate *' to 'QWidget *' Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
This works fine
tableView->setIndexWidget(index,new QLineEdit);