无法将TableViewCell类型的值强制转换为“ NSIndexPath”

Question

Could not cast value of type 'Google_Books_1.BookTableViewCell' (0x105557600) to 'NSIndexPath' (0x1061cb438)

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("BookCell", forIndexPath: indexPath) as!BookTableViewCell
  ...
}


func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) {
        // let contact = ContactList![indexPath.row]
        performSegueWithIdentifier("BookDetailSegue", sender: indexPath)
    }
func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) {
        // let contact = ContactList![indexPath.row]
        performSegueWithIdentifier("BookDetailSegue", sender: indexPath)
    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "BookDetailSegue" {
            let vc = segue.destinationViewController as! BookDetailViewController

            let indexPath = sender as! NSIndexPath
            vc.book = self.bookList[indexPath.row] **//error is here**
            vc.index = indexPath.row
        }
    }

How to handle such error?

Answer 1

Declare an instance variable

var indexPath: NSIndexPath?

Then assign selected indexPath like bellow:

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
            // let contact = ContactList![indexPath.row]
            self.indexPath = indexPath
            performSegueWithIdentifier("BookDetailSegue", sender: indexPath)
        }

Now access the indexPath like this:

 override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
            if segue.identifier == "BookDetailSegue" {
                let vc = segue.destinationViewController as! BookDetailViewController

                vc.book = self.bookList[self.indexPath.row!] **//error is here**
                vc.index = indexPath.row
            }
        }

Hope this help you.

Answer 2

Why not base yourself on your tableView's indexPathForSelectedRow property instead?

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == "BookDetailSegue" {
        let vc = segue.destinationViewController as! BookDetailViewController
        if let indexPath =  tableView.indexPathForSelectedRow {
            vc.book = self.bookList[indexPath.row] **//error is here**
            vc.index = indexPath.row
        }
    }
}