QDataWidgetMapper && QSqlRelationalTableModel && QComboBox

[luca]

Hi all,
I need to use a QDataWidgetMapper to show data from an Sql table:
@
tableModel = new QSqlTableModel()
tableModel->setTable(TABELLA);
...
...
dataWidgetMapper = new QDataWidgetMapper(this);
dataWidgetMapper->setModel(tableModel);
dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
dataWidgetMapper->addMapping(ui->menuEdit, tableModel->fieldIndex("menu"));
...
...
@

This part works fine. Now I'd like to show the "available" menu in a QComboBox (and not in QLineEdit) because there is a vs_menu sql table that contain all the "menu name".

I tried this:
@
tableModel = new QSqlRelationalTableModel();
tableModel->setTable(TABELLA);
...
tableModel->setRelation(3, QSqlRelation("vs_menu", "nome", "nome"));
...
...
dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
dataWidgetMapper->addMapping(ui->menuComboBox, tableModel->fieldIndex("menu"));
dataWidgetMapper->setItemDelegate(new QSqlRelationalDelegate(this));
@

but the combo isn't populated...

What do I wrong...?

[maxoreli]

you must know that "tableModel->setTable(TABELLA); "this method does not select data from the table, but fetches its field information.For selecting data from your table, apply "tableModel->select()".
Try that and wait for seeing results.
[quote author="Luca" date="1309294719"]Hi all,
I need to use a QDataWidgetMapper to show data from an Sql table:
@
tableModel = new QSqlTableModel()
tableModel->setTable(TABELLA);

dataWidgetMapper = new QDataWidgetMapper(this);
dataWidgetMapper->setModel(tableModel);
dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
dataWidgetMapper->addMapping(ui->menuEdit, tableModel->fieldIndex("menu"));
...
...
@

This part works fine. Now I'd like to show the "available" menu in a QComboBox (and not in QLineEdit) because there is a vs_menu sql table that contain all the "menu name".

I tried this:
@
tableModel = new QSqlRelationalTableModel();
tableModel->setTable(TABELLA);
tableModel->setRelation(3, QSqlRelation("vs_menu", "nome", "nome"));
...
...
dataWidgetMapper->addMapping(ui->idEdit, tableModel->fieldIndex("id"));
dataWidgetMapper->addMapping(ui->descrizioneEdit, tableModel->fieldIndex("descrizione"));
dataWidgetMapper->addMapping(ui->nomeEdit, tableModel->fieldIndex("nome"));
dataWidgetMapper->addMapping(ui->menuComboBox, tableModel->fieldIndex("menu"));
dataWidgetMapper->setItemDelegate(new QSqlRelationalDelegate(this));
@

but the combo isn't populated...

What do I wrong...?[/quote]

[luca]

Thanks maxoreli,

I didn't write all code but I already used tableModel->select() . And I can see data in my widget except for QComboBox.

[sidewinder]

What about QComboBox's setModel() and setModelColumn() functions? Maybe you can use QComboBox without QDataWidgetMapper and connect signals from QComboBox to navigate in QDataWidgetMapper.

[luca]

[quote author="sidewinder" date="1309332836"]What about QComboBox's setModel() and setModelColumn() functions? Maybe you can use QComboBox without QDataWidgetMapper and connect signals from QComboBox to navigate in QDataWidgetMapper.[/quote]

There are a lot of possible solution but I'd like to know if it's possible to use a QDataWidgetMapper in conjunction with QSqlRelationalTableModel to populate a QComboBox and to select the right item in the QComboBox while navigating the table.

[luca]

So it isn't possible?

For now I solved populating the combo in the constructor and positioning the right element by hand while navigating.

Now what when I save with:
@
tableModel->submitAll();
@
How can I manage the right element in the combo to be saved in the DB?

[pate]

After addMapping to QComboBox,you should do this:

@ QSqlTableModel *relationalModel = tableModel->relationModel(i);
ui->menuComboBox->setModel(relationalModel);
ui->menuComboBox->setModelColumn(relationalModel->fieldIndex("menu"); @

[luca]

[quote author="pate" date="1311819665"]After addMapping to QComboBox,you should do this:

@ QSqlTableModel *relationalModel = tableModel->relationModel(i);
ui->menuComboBox->setModel(relationalModel);
ui->menuComboBox->setModelColumn(relationalModel->fieldIndex("menu");
@
[/quote]

What is "i" in :
@
QSqlTableModel *relationalModel = tableModel->relationModel(i);
@
?

[luca]

Ok, now I understand what you mean.

I tried this, now the combo get populated but if I navigate the table with:
@
dataWidgetMapper->toNext();
@

the combo doesn't change showed item...

Is it possible to do that or I must do it by hand?

[pate]

[quote author="Luca" date="1311879787"][quote author="pate" date="1311819665"]After addMapping to QComboBox,you should do this:

@ QSqlTableModel *relationalModel = tableModel->relationModel(i);
ui->menuComboBox->setModel(relationalModel);
ui->menuComboBox->setModelColumn(relationalModel->fieldIndex("menu");
@
[/quote]

What is "i" in :
@
QSqlTableModel *relationalModel = tableModel->relationModel(i);
@
?[/quote]

Sorry！It's the index of the field "menu".
Here it should be
@
QSqlTableModel *relationalModel = tableModel->relationModel(tableModel->fieldIndex("menu"));@