Updating a data in QTableView question

[MarkoSan]

Hi to all, especialy nearly divine entities like jacek, jpn, marcel, wysota and others!

So, like I said, I have a shopping cart of merchandize in QTableView. Record are now added as they should, but I bumped into following problem. Let's say the shopping cart contains:

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+========================+

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+========================+

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Now, the user chooses another sprite and instead of:

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+========================+

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+------------------------+
+ Sprite                 +
+ 2.44 1x 2.44           +
+========================+

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I would like updated quantity and subtotal (second line, second number is quantity, third number is subtotal) like this:

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 2x 4.88           +
+========================+

+========================+
+ Coca Cola              +
+ 1,00 1x 1.00           +
+------------------------+
+ Sprite                 +
+ 2.44 2x 4.88           +
+========================+

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Now, here is a code chunck that should do this:

else
    {
        // merchandize found, update quantity and subtotal
        qDebug() << "iRemberedMerchandizeID:" << iRemberedMerchandizeID;    // debug output
        CMerchandizeOrder* pUpdatedOrder=new CMerchandizeOrder(order);    // gets order to update
        Q_CHECK_PTR(pUpdatedOrder);    // checks creation
        structOrder updatedOrderStruct=pUpdatedOrder->orderValues();    // gets order's struct
 
        updatedOrderStruct.iMerchandizeQuantity++;    // increase quantity
        updatedOrderStruct.rSubtotal=updatedOrderStruct.iMerchandizeQuantity*updatedOrderStruct.rMerchandizePrice;    // updates subtotal
        pUpdatedOrder->setMerchandizeQuantity(updatedOrderStruct.iMerchandizeQuantity);
        pUpdatedOrder->setSubtotal(updatedOrderStruct.rSubtotal);
        pUpdatedOrder->setDisplayString(updatedOrderStruct);
        m_pShoppingCartModel->orders().replace(iRememberedIndex, pUpdatedOrder);
        QModelIndex index=shoppingCartModel()->index(0, 0, QModelIndex());
        shoppingCartModel()->setData(index,
                                     pUpdatedOrder->orderValues().strDisplayString,
                                     Qt::EditRole);
        emit dataChanged(index, index);
    }
    // TODO: update grand total field

else
    {
        // merchandize found, update quantity and subtotal
        qDebug() << "iRemberedMerchandizeID:" << iRemberedMerchandizeID;    // debug output
        CMerchandizeOrder* pUpdatedOrder=new CMerchandizeOrder(order);    // gets order to update
        Q_CHECK_PTR(pUpdatedOrder);    // checks creation
        structOrder updatedOrderStruct=pUpdatedOrder->orderValues();    // gets order's struct
        
        updatedOrderStruct.iMerchandizeQuantity++;    // increase quantity
        updatedOrderStruct.rSubtotal=updatedOrderStruct.iMerchandizeQuantity*updatedOrderStruct.rMerchandizePrice;    // updates subtotal
        pUpdatedOrder->setMerchandizeQuantity(updatedOrderStruct.iMerchandizeQuantity);
        pUpdatedOrder->setSubtotal(updatedOrderStruct.rSubtotal);
        pUpdatedOrder->setDisplayString(updatedOrderStruct);
        m_pShoppingCartModel->orders().replace(iRememberedIndex, pUpdatedOrder);
        QModelIndex index=shoppingCartModel()->index(0, 0, QModelIndex());
        shoppingCartModel()->setData(index,
                                     pUpdatedOrder->orderValues().strDisplayString,
                                     Qt::EditRole);
        emit dataChanged(index, index);
    }
    // TODO: update grand total field

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but the cell is not updated, i.e., nothing happens. The code is a part of bigger if clause, and I've set breakpoint in the begining of this code chunk to check if the IF clause works ok. It does. I've checked with debugger, data are recalculated correctly (quantity and subtotal), but the contenst of QTableView are not updatet. Why?!

[MarkoSan]

No one has idea what is wrong?

[janus]

Why is dataChanged emitted from this function. I thought it is called from setData() ?!

I found this post. Maybe this is something similar.

QSqlQueryModel is read only, that's one thing. Changing the record doesn't modify the database (record() returns a copy of the record), that's another thing.

http://www.qtcentre.org/forum/f-qt-p...lue-11762.html

Actually i have the same problem: Can not change a Record filed value inside of setData in a subclassed QueryModel.

[MarkoSan]

Sorry, I forgot to delete emitData(). You were right, emitData is called from my setData(). So, my model is subclassed from QAbstractTableModel, you think I have to make it editable for operation I want to achieve?

[MarkoSan]

And how to delete item from model (from tableview) if necessary. I do not know how to get index (row) of selected item.

[jpn]

And how to delete item from model (from tableview) if necessary.

Use QAbstractItemModel::removeRows(), or if you're using QStandardItems I believe you can simply delete them.

I do not know how to get index (row) of selected item.

• QAbstractItemView::selectedIndexes()
• QAbstractItemView::selectionModel()