void Dialog_graph::closeEvent(QCloseEvent *event) {
... // do some actions
event->accept(); // this line generates a compiler error!
}

Fehler: invalid use of incomplete type »struct QCloseEvent«

In my application there shall be some actions before finally closing a dialog.
The following code shall do this:
Quote:

void Dialog_graph::closeEvent(QCloseEvent *event) {
... // do some actions
event->accept(); // this line generates a compiler error!
}

In another application I did it exactly the same way with the main window. And it runs.

Now I want to do it with the dialog (Dialog_graph) but the compiler generates an error:
Quote:

Fehler: invalid use of incomplete type »struct QCloseEvent«

What is wrong?