iOS how to get a reference to a view controller embedded in a storyboard container with a segue?

Question

I have a storyboard and a view controller with a container view. Within a storyboard I've defined a connection from the container to another view controller using "Embed" segue. How can I get a reference to the embedded view controller from within a parent view controller?

I've created a reference to the container, but see that it is just a UIView

Here's the segue I'm using

Answer 1

you must implement the prepareForSegue in main ViewController and specify an identifier in your StoryBoard.

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Make sure your segue name in storyboard is the same as this line
    if ([[segue identifier] isEqualToString:@"YOUR_SEGUE_NAME_HERE"])
    {
        // Get reference to the destination view controller
        YourViewController *vc = [segue destinationViewController];

    }
}

Answer 2

Same answer as above, but in swift:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "nameOfSegueIdentiferFromStoryboard") {
        guard let destinationVC = segue.destination as? ViewControllerClassName else { return }
        destinationVC.someProperty = someValue
    }
}