QSqlRelationalTableModel Dopdown List for Field

Andy314

Hello,
I want in a qtableview (DamTV) a Dropdown-Listbox for a special column.

QSqlRelationalTableModel Dams;
Dams.setEditStrategy(QSqlTableModel::OnFieldChange);
Dams.setTable(tblDamageTemplate);
Dams.setRelation(4, QSqlRelation("qlkp_DamPart", "ID", "SCDesc"));
ui->DamTV->setModel(&Dams);
ui->DamTV->setItemDelegateForColumn(4, new QSqlRelationalDelegate(this));
Dams.select();

After select all is correct, I see instead of the primary key the lookup text in column 4.
When I select a field and leave the field I see the primary key (ID).

Why is that ? Why changes the editor the view representation of the data ?
This should be independent when I understand the concept correctly.

SGaist

Hi,,

Where are you using this code ?

Andy314

@SGaist
In the constructor of the dialog after ui->setupUi(this);
QSqlRelationalTableModel Dams; is of course in the header of the dialog.

SGaist

Which OS and Qt version ?

Andy314

Qt 5.6.0 32-bit, MSVC 2015, Windows 10 64-bit

If found the code for the QSqlRelationalDelegate, have made a renamed copy of it for testing.

class QSqlRelationalDelegate2: public QItemDelegate
{
public:
    explicit QSqlRelationalDelegate2(QObject *aParent = 0)
        : QItemDelegate(aParent)  {}
    ~QSqlRelationalDelegate2()  {}

    QWidget *createEditor(QWidget *aParent,
                          const QStyleOptionViewItem &option,
                          const QModelIndex &index) const
    {
        const QSqlRelationalTableModel *sqlModel
                = qobject_cast<const QSqlRelationalTableModel *>(index.model());
        QSqlTableModel *childModel = sqlModel ? sqlModel->relationModel(index.column()) : 0;
        if (!childModel)
            return QItemDelegate::createEditor(aParent, option, index);

        QComboBox *combo = new QComboBox(aParent);
        combo->setModel(childModel);
        combo->setModelColumn(childModel->fieldIndex(sqlModel->relation(
                                index.column()).displayColumn()));
        combo->installEventFilter(const_cast<QSqlRelationalDelegate2 *>(this));

        return combo;
    }

    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
    {
        if (!index.isValid())
            return;

        QSqlRelationalTableModel *sqlModel = qobject_cast<QSqlRelationalTableModel *>(model);
        QSqlTableModel *childModel = sqlModel ? sqlModel->relationModel(index.column()) : 0;
        QComboBox *combo = qobject_cast<QComboBox *>(editor);
        if (!sqlModel || !childModel || !combo) {
            QItemDelegate::setModelData(editor, model, index);
            return;
        }
//        QSqlRelation newrel(sqlModel->relation(index.column()));

        int currentItem = combo->currentIndex();
        int childColIndex = childModel->fieldIndex(sqlModel->relation(index.column()).displayColumn());
        int childEditIndex = childModel->fieldIndex(sqlModel->relation(index.column()).indexColumn());

        QString dd=childModel->data(childModel
                ->index(currentItem, childColIndex), Qt::DisplayRole).toString();

        sqlModel->setData(index,
                childModel->data(childModel->index(currentItem, childColIndex),
                Qt::DisplayRole), Qt::DisplayRole);
        sqlModel->setData(index,
                childModel->data(childModel->index(currentItem, childEditIndex),
                Qt::EditRole), Qt::EditRole);
//        sqlModel->setRelation(index.column(), newrel);
//        sqlModel->dataChanged(index, index,
//                QVector<int>()<<Qt::DisplayRole<<Qt::EditRole);
    }
    void paint(QPainter* painter,   const QStyleOptionViewItem& opt,
               const QModelIndex& index) const
    {
        QString s=index.data(Qt::DisplayRole).toString();
        QStyleOptionViewItem so=opt;
        drawDisplay(painter, so, so.rect, s);
        return;
    }
};

Not even the overwriting of the paint function help. Should not have the delegate the control for the painting always ?

In the setModelData function the last command

        sqlModel->setData(index,
                childModel->data(childModel->index(currentItem, childEditIndex),
                Qt::EditRole), Qt::EditRole);

makes the problem. After write back the data from the widget to the model I get the view shows the foreign key and not its lookup.

Andy314

I found the delegate has indeed ever the control for the painting. Before editing all works.
The problem is that after setModelData both the Display- and Editrole give always the foreign key for the changed cell.

QString s1=index.data(Qt::DisplayRole).toString();
QString s2=index.data(Qt::EditRole).toString();

SGaist

Can you provide a minimal compilable example that reproduce that behaviour ?