wysota, will fix that, now it is mandatory to make the code work. Here is the code that uses model:
Qt Code: 
  1. // slot for choosing merchandize
  2. void COperationWIndow::chooseMerchandize()
  3. {
  4.     structOrder tmpOrder;    // temp order
  5.     QList<QStandardItem*> OrderItemList;    // order model item list
  6.  
  7.     qDebug() << "m_iSelected: " << m_pMerchandizeBrowser->m_iSelected;
  8.     // FIXED: m_pMerchandizeBrowser->m_iSelected does not correctly show the index of selected image
  9. /*
  10.     tmpOrder.iMerchandizeID=1;
  11.     tmpOrder.iMerchandizeQuantity=25;
  12.     tmpOrder.rMerchandizePrice=4.00;
  13.     tmpOrder.rSubtotal=tmpOrder.iMerchandizeQuantity*tmpOrder.rMerchandizePrice;
  14.     tmpOrder.strMerchandizeName=QString("Testni Artikel");
  15.     tmpOrder.strDisplayString=QString::number(tmpOrder.iMerchandizeID)+strMerchandizeSpaceDelimiter+\
  16.                               QString(tmpOrder.strMerchandizeName)+strMerchandizeDelimiter+\
  17.                               QString::number(tmpOrder.rMerchandizePrice, 'f', iMerchandizePricePrecision)+strMerchandizeSpaceDelimiter+\
  18.                               QString::number(tmpOrder.iMerchandizeQuantity)+strMerchandizeSpaceDelimiter+\
  19.                               QString::number(tmpOrder.rSubtotal, 'f', iMerchandizePricePrecision);
  20.     qDebug() << "tmpOrder.strDisplayString=" << tmpOrder.strDisplayString;
  21. */
  22.  
  23.     // TODO: language id number must not be ignored in sql statement
  24.     QString queryString("SELECT * from merchandize WHERE IdentificationNumber=%1 AND InUse=1;");
  25.     int iMerchandizeId=m_pMerchandizeBrowser->m_iSelected+1;    // calcualtes id
  26.     queryString=queryString.arg(iMerchandizeId);    // adds id to query string
  27.     qDebug() << "Query: " << queryString;    // debug
  28.     QSqlQuery query(queryString);    // sets up query from query string
  29.     qDebug() << query.lastError().text();    // debug
  30.     if (query.isActive())
  31.     {
  32.         while (query.next())
  33.         {
  34.             tmpOrder.iMerchandizeID=query.value(0).toInt();
  35.             tmpOrder.iMerchandizeQuantity=1;
  36.             tmpOrder.rMerchandizePrice=(qreal)query.value(3).toDouble();
  37.             tmpOrder.rSubtotal=tmpOrder.iMerchandizeQuantity*tmpOrder.rMerchandizePrice;
  38.             tmpOrder.strMerchandizeName=QString(query.value(2).toString());
  39.             tmpOrder.strDisplayString=QString::number(tmpOrder.iMerchandizeID)+strMerchandizeSpaceDelimiter+\
  40.                                       QString(tmpOrder.strMerchandizeName)+strMerchandizeDelimiter+\
  41.                                       QString::number(tmpOrder.rMerchandizePrice, 'f', iMerchandizePricePrecision)+strMerchandizeSpaceDelimiter+\
  42.                                       QString::number(tmpOrder.iMerchandizeQuantity)+strMerchandizeSpaceDelimiter+\
  43.                                       QString::number(tmpOrder.rSubtotal, 'f', iMerchandizePricePrecision);
  44.         }
  45.  
  46.  
  47.         if(m_pShoppingCartView->order()->orders()->size()<=0)
  48.         {
  49.             // size of orders is zero, adds record to table
  50.             m_pShoppingCartView->order()->orders()->append(tmpOrder);    // adds order to internal qlist
  51.             QStandardItem* pItem=new QStandardItem(QString(tmpOrder.strDisplayString));
  52.             Q_CHECK_PTR(pItem);    // checks creation
  53.             m_pShoppingCartView->shoppingCartModel()->appendRow(pItem);
  54.         }
  55.         else
  56.         {
  57.             for(qint16 iIndex=0; iIndex<(qint16)m_pShoppingCartView->order()->orders()->size(); iIndex++)
  58.             {
  59.                 qDebug() << " m_pShoppingCartView->order()->orders()->at((int)iIndex).iMerchandizeID (" \
  60.                          << m_pShoppingCartView->order()->orders()->at((int)iIndex).iMerchandizeID << ")==" \
  61.                          << "tmpOrder.iMerchandizeID (" << tmpOrder.iMerchandizeID << ")?";
  62.                 if(m_pShoppingCartView->order()->orders()->at((int)iIndex).iMerchandizeID==tmpOrder.iMerchandizeID)
  63. /*
  64.                 qDebug() << " iMerchandizeId (" << iMerchandizeId \
  65.                          << "tmpOrder.iMerchandizeID (" << tmpOrder.iMerchandizeID << ")?";
  66.                 if(iMerchandizeId==tmpOrder.iMerchandizeID)
  67. */
  68.                 {
  69.                     // orderer merchandize found, so
  70.                     tmpOrder.iMerchandizeQuantity++;    // update quantity
  71.                     tmpOrder.rSubtotal=tmpOrder.iMerchandizeQuantity*tmpOrder.rMerchandizePrice;    // update total
  72.                     tmpOrder.strDisplayString=QString::number(tmpOrder.iMerchandizeID)+strMerchandizeSpaceDelimiter+\
  73.                                               QString(tmpOrder.strMerchandizeName)+strMerchandizeDelimiter+\
  74.                                               QString::number(tmpOrder.rMerchandizePrice, 'f', iMerchandizePricePrecision)+strMerchandizeSpaceDelimiter+\
  75.                                               QString::number(tmpOrder.iMerchandizeQuantity)+strMerchandizeSpaceDelimiter+\
  76.                                               QString::number(tmpOrder.rSubtotal, 'f', iMerchandizePricePrecision);
  77.                     m_pShoppingCartView->order()->orders()->replace((int)iIndex, tmpOrder);    // saves changes
  78.                     m_pShoppingCartView->shoppingCartModel()->clear();    // clears table view
  79.                     for(qint16 iIndex=0; iIndex<(qint16)m_pShoppingCartView->order()->orders()->size(); iIndex++)
  80.                     {
  81.                         QStandardItem* pItem=new QStandardItem(QString(tmpOrder.strDisplayString));    // creates new item from order
  82.                         Q_CHECK_PTR(pItem);    // checks creation
  83.                         OrderItemList.append(pItem);    // adds item to list
  84.                         //m_pShoppingCartView->shoppingCartModel()->appendRow(pItem);    // adds items
  85.                     }
  86.                     m_pShoppingCartView->shoppingCartModel()->appendRow(OrderItemList);    // adds items
  87.                     break;
  88.                 }
  89.                 else
  90.                 {
  91.                     // ordered merchandize not found, so adds it
  92.                     m_pShoppingCartView->order()->orders()->append(tmpOrder);    // adds order to internal qlist
  93.                     QStandardItem* pItem=new QStandardItem(QString(tmpOrder.strDisplayString));    // creates new item from list
  94.                     Q_CHECK_PTR(pItem);    // checks creation
  95.                     m_pShoppingCartView->shoppingCartModel()->appendRow(pItem);
  96.                     break;
  97.                 }    // for
  98.             }    // for
  99.         }    // if
  100. /*
  101.         m_pShoppingCartView->resizeColumnsToContents();
  102.         m_pShoppingCartView->resizeRowsToContents();
  103. */
  104.         if(m_pOrderButton->isEnabled()==false)
  105.             m_pOrderButton->setEnabled(true);    // enables order buttn
  106.     }    // if
  107. }
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The code
Qt Code: 
  1. /*
  2.         m_pShoppingCartView->resizeColumnsToContents();
  3.         m_pShoppingCartView->resizeRowsToContents();
  4. */
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is commented because here the app crashes by resizeRows. Why?!