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           +
+========================+

To copy to clipboard, switch view to plain text mode 

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           +
+========================+

To copy to clipboard, switch view to plain text mode 

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           +
+========================+

To copy to clipboard, switch view to plain text mode 

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

To copy to clipboard, switch view to plain text mode 

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?!