Why is it invalid using value() of QSqlRecord?

[CoderJeff]

    QSqlTableModel *tblModel = (QSqlTableModel*)ui->tableView->model();
    tblModel->setTable("TableTest");
    QSqlRecord rec = tblModel->record(ui->tableView->currentIndex().row());
    QVariant var;
    if(!rec.isEmpty())
    {
        var = rec.value(0);
    }

Although rec is not empty, var is always invalid.

Why?

[koahnig]

@CoderJeff

How do you use var?
You might have to use one of those methods e.g. toDouble().

[CoderJeff]

@koahnig

Before using toDouble or other methods, var should be valid. But it is always invalid in fact.

I tried using toInt and toString, and the result was always 0.

[JKSH]

@CoderJeff said:

QSqlRecord rec = tblModel->record(ui->tableView->currentIndex().row());

What is the value of ui->tableView->currentIndex().row()?