[SOLVED] [QComboBox and QSqlRelationalDelegate] How to show conditional content in a QComboBox

valandil211

Hello Qt Devs!

For my GUI to a PostgreSQL DB, I want to show data in combo boxes. However, some of my data has something alike a tree-structure. In short, I want the data in a second ComboBox to be affected by the data in a first ComboBox.

It seems to be doable with a relational delegate, but it doesn't quite work.

@// Populate the group ComboBox
groupModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("******"));
groupModel->setTable(""TB_Groupe"");
groupModel->setSort(groupModel->fieldIndex("GR_Nom"), Qt::AscendingOrder);
groupModel->select();

ui->MW_groupComboBox->setModel(groupModel);
ui->MW_groupComboBox->setModelColumn(groupModel->fieldIndex("GR_Nom"));

catModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("*****"));
catModel->setTable("\"TB_Categorie\"");
catModel->setSort(catModel->fieldIndex("CAT_Nom"), Qt::AscendingOrder);
catModel->setRelation(1, QSqlRelation("\"TB_Groupe\"","IndexCategorie", "GR_Nom"));
catModel->select();

ui->MW_catComboBox->setModel(catModel);
ui->MW_catComboBox->setModelColumn(catModel->fieldIndex("CAT_Nom"));@

Any ideas?

valandil211

This does not seem to work, either.

@// Populate the group ComboBox
groupModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("*****"));
groupModel->setTable(""TB_Groupe"");
groupModel->setSort(groupModel->fieldIndex("GR_Nom"), Qt::AscendingOrder);
groupModel->select();

ui->MW_groupComboBox->setModel(groupModel);
ui->MW_groupComboBox->setModelColumn(groupModel->fieldIndex("GR_Nom"));

// Populate category ComboBox according to Group ComboBox
catModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("*******"));
catModel->setTable("\"TB_Categorie\"");
catModel->setSort(catModel->fieldIndex("CAT_Nom"), Qt::AscendingOrder);
catModel->setFilter("CAT_IndexGroupe =" % ui->MW_groupComboBox->currentIndex());
catModel->select();

ui->MW_catComboBox->setModel(catModel);
ui->MW_catComboBox->setModelColumn(catModel->fieldIndex("CAT_Nom"));@

valandil211

Found easy solution by using signals and slots. This system rocks!

@// Populate the group ComboBox
groupModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("******"));
groupModel->setTable(""TB_Groupe"");
groupModel->setSort(groupModel->fieldIndex("GR_Nom"), Qt::AscendingOrder);
groupModel->select();

ui->MW_groupComboBox->setModel(groupModel);
ui->MW_groupComboBox->setModelColumn(groupModel->fieldIndex("GR_Nom"));

// Populate category ComboBox according to Group ComboBox
catModel = new QSqlRelationalTableModel(this, QSqlDatabase::database("*******"));
catModel->setTable("\"TB_Categorie\"");
catModel->setFilter("\"CAT_IndexGroupe\" = " % QString::number(ui->MW_groupComboBox->currentIndex()+1));
catModel->setSort(catModel->fieldIndex("CAT_Nom"), Qt::AscendingOrder);
catModel->select();

ui->MW_catComboBox->setModel(catModel);
ui->MW_catComboBox->setModelColumn(catModel->fieldIndex("CAT_Nom"));

connect(ui->MW_groupComboBox,
        SIGNAL(currentIndexChanged(int)),
        this,
        SLOT(RefreshCategory(int)));

}

void MainWindow::RefreshCategory(int choice)
{
catModel->setFilter(""CAT_IndexGroupe" = " % QString::number(choice+1));
catModel->select();

ui->MW_catComboBox->setModel(catModel);
ui->MW_catComboBox->setModelColumn(catModel->fieldIndex("CAT_Nom"));

}@