Crash on removing a row

[inktomi]

Hi,

I'm trying to remove a row from a QTableWidget using removeRow(...) and the application crashes. When I remove a row other than row 0, it usually doesn't crash, however removing row 0 always crashes.

The application crashes with:
ASSERT failure in QList<T>:perator[]: "index out of range", file c:/Qt/2009.03/qt/include/QtCore/../../src/corelib/tools/qlist.h, line 403

I saw a similar situation on this forum, with no real solution.

Any replies are appreciated. Thank you.

[navi1084]

before removing the row check the current Index. Seems to be deleting the item which are not there in the list. Use currentRow() and check whether return value is -1 or 0. if return value is -1, then if u r trying to delete definitely application crashes

[nish]

can you post a little bit of your code?

[inktomi]

currentRow() is returning the correct value.

Here's the code, triggered when a button is clicked. The row index is correct because I printed the value in the console. I even hardcoded the application to remove row index 0 and it still crashes.

void MainWindow::on_removeButton_clicked()
{
    QList<QTableWidgetItem *> selectedItems = ui->clipListWidget->selectedItems();
    if ((ui->clipListWidget->rowCount() > 0) && (selectedItems.count() > 0))
    {
        ui->clipListWidget->removeRow(selectedItems[0]->row());
    }
}

void MainWindow::on_removeButton_clicked()
{
    QList<QTableWidgetItem *> selectedItems = ui->clipListWidget->selectedItems();
    if ((ui->clipListWidget->rowCount() > 0) && (selectedItems.count() > 0))
    {
        ui->clipListWidget->removeRow(selectedItems[0]->row());
    }
}

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[nish]

try to clear the selection of item first before removing

selectedItems[0]->setSelected(false);
ui->clipListWidget->removeRow(selectedItems[0]->row());

selectedItems[0]->setSelected(false);
ui->clipListWidget->removeRow(selectedItems[0]->row());

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also make sure the you do not access the item anywhere else

if you single step in debugger .. on which line it crashes?

[inktomi]

It crashes on:

ui->clipListWidget->removeRow(selectedItems[0]->row());

ui->clipListWidget->removeRow(selectedItems[0]->row());

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Apparently its not letting me modify any properties of selected items. Not even unselecting selected items.

[nish]

ok.. can you produce a minimal compilable example reproducing the problem?

[inktomi]

I've tried to reprodce it but it is not happening.

I've now tried to unselect all items one after the other. All is fine until I unselect the last item. When I do, I get the 'index out of range' crash.

EDIT: Turns out that the crash was caused in the SelectionChanged event. When the last row was being removed, the selection event was being triggered, but it wasn't handling the 'nothing selected' case correctly.

[inktomi]

Sorry for bothering you. Seems I still can't use the debugger correctly.

[Nickolay]

I'm also have such problem - crash on deleting row = 0.
Also read many topics and try different decisions,
but nothing help me.

But seems solutions is found,at least for me it sufficient:

in QtDesigner -> property page of QTableWidget and set -> SelectionBehavior -> SelectRows

tableNotifications->setSelectionBehavior(QAbstractItemView::SelectRows);

tableNotifications->setSelectionBehavior(QAbstractItemView::SelectRows);

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due to this, now I call deleteRow(0) and all works! without crash.

[wysota]

Be sure not to delete items from within slots connected to signals that have the item (or its index) as their parameter.