protected override void OnClosing(CancelEventArgs e)
{
if (_actuallyClosing)
{
_actuallyClosing = false;
return;
}
if (_deferredClosing)
{
return;
}
base.OnClosing(e);
var closingEventArgs = new ClosingEventArgs()
{
Cancel = e.Cancel
};
var deferredEvent = Closing.InvokeAsync(this, closingEventArgs);
if (deferredEvent.IsCompleted)
{
e.Cancel = closingEventArgs.Cancel;
}
else
{
e.Cancel = true;
_deferredClosing = true;
DeferredClose(deferredEvent, closingEventArgs);
}
}
