the question about define my own selection behavior

[calmspeaker]

Hi ,all

Recently, I use tableview to make an alarm window which ,obviously, show the alarms in in the scada system.

The requirement is: If the operator is permitted by his privilege to ack the alarm in the alarm window,he can select the alarm, if not, he cannot select.

I inherit QTableView and rewrite the function

QItemSelectionModel::SelectionFlags QAbstractItemView::selectionCommand(const QModelIndex &index, const QEvent *event) const

QItemSelectionModel::SelectionFlags QAbstractItemView::selectionCommand(const QModelIndex &index, const QEvent *event) const

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the code is like this:

QItemSelectionModel::SelectionFlags CAckTableView::selectionCommand ( const QModelIndex & index, const QEvent * event) const
{
	if (the operator does not have privilege){
		return QItemSelectionModel::NoUpdate | QItemSelectionModel::current;
	}
 
	return QTableView::selectionCommand(index,event);
 
}

QItemSelectionModel::SelectionFlags CAckTableView::selectionCommand ( const QModelIndex & index, const QEvent * event) const
{
	if (the operator does not have privilege){
		return QItemSelectionModel::NoUpdate | QItemSelectionModel::current;
	}

	return QTableView::selectionCommand(index,event);
	
}

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Then I found the selcet event QEvent::MouseButtonPress act
properly,but QEvent::MouseMove is very strange.

The selection behavior of QEvent::MouseMove is depend on the last item the mouse pointer on. That is hard to describe clearly. Finally I probably find the problem in the qt source code. In

void QAbstractItemView::mouseMoveEvent(QMouseEvent *event)

void QAbstractItemView::mouseMoveEvent(QMouseEvent *event)

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,
call

setSelection(selectionRect, command);

setSelection(selectionRect, command);

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,

the parameter is

QPoint topLeft;   
if (d->selectionMode != SingleSelection)
        topLeft = d->pressedPosition - d->offset();
else
        topLeft = bottomRight;
 QPoint bottomRight = event->pos();
QRect selectionRect = QRect(topLeft, bottomRight);
 
QModelIndex index = indexAt(bottomRight);
 QItemSelectionModel::SelectionFlags command = selectionCommand(index, event);

QPoint topLeft;   
if (d->selectionMode != SingleSelection)
        topLeft = d->pressedPosition - d->offset();
else
        topLeft = bottomRight;
 QPoint bottomRight = event->pos();
QRect selectionRect = QRect(topLeft, bottomRight);

QModelIndex index = indexAt(bottomRight);
 QItemSelectionModel::SelectionFlags command = selectionCommand(index, event);

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In coclusion the problem is: the selection of MouseMove event is depend on whether the operator has the privilge on the last item the mouse pointed. The privilege cannot work!!

I think the problem is in the

void QAbstractItemView::mouseMoveEvent(QMouseEvent *event)

void QAbstractItemView::mouseMoveEvent(QMouseEvent *event)

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.
Did anyone meet such problem? Please give me a clue! Thank you!

[shentian]

You don't need to modify the selection model. You can tell the view which items can be selected by using the Qt::ItemIsSelectable flag in your data model.

Inherit your model and overwrite QAbstractItemModel::flags:

Qt::ItemFlags MyModel::flags(const QModelIndex& index) const
{
  if (/* user is allowd to select index.row() */)
    return QAbstractTableModel::flags(index) | Qt::ItemIsSelectable;
  else
    return QAbstractTableModel::flags(index) & ~Qt::ItemIsSelectable;
}

Qt::ItemFlags MyModel::flags(const QModelIndex& index) const
{
  if (/* user is allowd to select index.row() */)
    return QAbstractTableModel::flags(index) | Qt::ItemIsSelectable;
  else
    return QAbstractTableModel::flags(index) & ~Qt::ItemIsSelectable;
}

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