将数据从ViewController传递回根ViewController？

Question

I wonder how I can pass data between VC3 and VC1.

What I have is a root view(VC1). Then you enter a tableView and if you pick an item you will enter tableView2(VC3) - category - sub category picker.

What I have done so far is to declare this in VC1:

@IBAction func unwindToVC1(segue: UIStoryboardSegue) {

 }

Then in story board I control-dragged the yellow button to the red button in VC3 and choose "unwindToVC1" as the action, then I named the segue.

I then fire the segue in VC3 by performSegueWithIdentifier()

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "Vc1" {
            let toView = segue.destinationViewController as! myRootVc

            let test = "test string"

            toView.test = test

        }
    }

It almost works, I end up in VC1 but the passed value shows up as nil in VC1, even though I have it declared in vc1 since before:

var test: String?

Answer 1

you are using segues to pass data between VC! and VC3 an when you have selcted anitem from sub category. you can use Delegates