tableview and pushbutton connection

[Coises]

I'm trying to make the button enabled when some of the tableview row is selected

This one is a bit more complicated than you would expect. The signal you need doesn’t come directly from QTableView, but from the QItemSelectionModel associated with it.

connect(ui->tableView_clients->selectionModel(),SIGNAL(currentRowChanged(QModelIndex, QModelIndex)),SLOT(enableCheck(QModelIndex, QModelIndex)));
 
...
 
void enableCheck(const QModelIndex& current, const QModelIndex& previous) {
    ui->pushButton_select->setEnabled(current.isValid());
}

connect(ui->tableView_clients->selectionModel(),SIGNAL(currentRowChanged(QModelIndex, QModelIndex)),SLOT(enableCheck(QModelIndex, QModelIndex)));

...

void enableCheck(const QModelIndex& current, const QModelIndex& previous) {
    ui->pushButton_select->setEnabled(current.isValid());
}

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Since setEnabled requires a bool argument, and the signal you need doesn’t have one, you can’t connect them directly.

Zlatomir’s idea will also work, though he named the wrong method. QAbstractItemView::selectionChanged is a virtual protected slot that is called when the selection changes. If it isn’t already, you would have to make tableView_clients an instance of a subclass of QTableView — remembering the Q_OBJECT macro! — and define a signal which you would connect to QPushButton::setEnabled(bool); then override the selectionChanged method and have it call the base method, then emit that signal.