Xcode Segue "Could not cast value of type"

Question

I have segues going to two different ViewControllers, Detail & Search. The segues going to Detail are working fine, but the one going to Search keeps crashing the app. I have spent two hours reading similar questions but none of them seem to have the same issue:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    let detailVC = segue.destination as! DetailViewController

    if segue.identifier == "newDocSegue"   {
        // Create a new document and pass it to the detail view.
        detailVC.doc = Document()
        detailVC.isAddAction = true
    }

    if segue.identifier == "editDocSegue"    {
        // Load the existing document into the detail view, for editing.
        let indexPath = tableView.indexPath(for: sender as! UITableViewCell)!
        detailVC.doc = Document[indexPath.row]
        detailVC.isAddAction = false
    }
     else if segue.identifier == "searchSegue" {
        shouldPerformSegue(withIdentifier: "searchSegue", sender: Any?.self)
    }

}

The segues are going from a TableViewController to ViewControllers — orange-oc, Feb 13 '17 at 06:59
shouldPerformSegue(withIdentifier: "searchSegue", sender: Any?.self), why this line is there? — Ravi, Feb 13 '17 at 07:04
you are missing an `else` on your second if statement as well — Fonix, Feb 13 '17 at 07:07

score 3 · Accepted Answer · answered Feb 13 '17 at 07:06

Your problem is the

let detailVC = segue.destination as! DetailViewController

line. This will attempt to cast any VC (including your search VC) as a DetailViewController. Try this:

let detailVC : UIViewController

if segue.identifier == "newDocSegue"   {
    // Create a new document and pass it to the detail view.
    detailVC = segue.destination as! DetailViewController
    detailVC.doc = Document()
    detailVC.isAddAction = true
}

if segue.identifier == "editDocSegue"    {
    // Load the existing document into the detail view, for editing.
    detailVC = segue.destination as! ???  // not sure what type you want here
    let indexPath = tableView.indexPath(for: sender as! UITableViewCell)!
    detailVC.doc = Document[indexPath.row]
    detailVC.isAddAction = false
}
 else if segue.identifier == "searchSegue" {
    detailVC = segue.destination as! SearchViewController
    shouldPerformSegue(withIdentifier: "searchSegue", sender: Any?.self)
}

Thank you. This answered it. I moved the let statement inside of the first two segues. — orange-oc, Feb 13 '17 at 18:37

score 0 · Answer 2 · edited Feb 13 '17 at 07:41

0

Your problem is at:

let detailVC = segue.destination as! DetailViewController

if your destination's type is SearchViewController cast will cause error

Try this:

if let detailVC = segue.destination as? DetailViewController

You should be aware about as? and as!

edited Feb 13 '17 at 07:41

sazzad

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answered Feb 13 '17 at 07:19

Nguyễn Anh Việt

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That makes sense. Thank you. – orange-oc Feb 13 '17 at 18:37

Xcode Segue "Could not cast value of type"

2 Answers2