Problem with updating QTreeView with QAbstractITemModel

[Mohsin]

Currently, there is a problem with line number 5, QT doesn't allow to change the QTreeWidget model.

Is there a view to fixing this problem? instead of using QtreeView.

QAbstractItemModel * sourceModel;
   sourceModel = ui->treeWidget->model();
   QSortFilterProxyModel *proxyModel = new QSortFilterProxyModel(this);
   proxyModel->setSourceModel(sourceModel);
   ui->treeWidget->QTreeWidget::setModel(proxyModel);

QAbstractItemModel * sourceModel;
   sourceModel = ui->treeWidget->model();
   QSortFilterProxyModel *proxyModel = new QSortFilterProxyModel(this);
   proxyModel->setSourceModel(sourceModel);
   ui->treeWidget->QTreeWidget::setModel(proxyModel);

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[ChristianEhrlicher]

You must not change the model of a QTree/Table/ListWidget - if you want to set a custom model, use the corresponding QTree/Table/ListView classes.
You don't need a QSortFilterProxyModel for a QTreeWidget. See the documentation how to achieve sorting there: https://doc.qt.io/qt-5/qtreewidgetitem.html#operator-lt