prepareForSegue方法中出现错误“无法分配类型的值”（Swift，Xcode 6）

Question

I just want to make a segue by an example here http://www.codingexplorer.com/segue-uitableviewcell-taps-swift/

But when I made this code:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue.identifier == blogSegueIdentifier {
        if let destination = segue.destinationViewController as? specialitiesViewController {
            if let cellIndex = tableView.indexPathForSelectedRow()?.row {
                destination.formuleName = formulesList[cellIndex]
            }
        }
    }
}

Appeared error called:

cannot assign a value of type '(Formules)' to a value of type String"

this is a class which contents a data for formuleList

formuleList is an array with a list of cell names

how to remove error? Thank u for your help.

Answer 1

The way that this segue block works is you are basically telling the UI that I'm going to segue to the next view controller

if let destination = segue.destinationViewController as? specialitiesViewController if let destination = segue.destinationViewController as? specialitiesViewController - says that the ViewController we are going to is of custom type specialitiesViewController

My assumption would be that in your specialitiesViewController you have a variable called forumlaName that is of type String and that your formulesList is of type [Formules] - and as such this assignment is invalid.

You are trying to assign a specific Formules to a String and thus occurs your error.

Fix choices would be to make sure the type Formules implements one of the String protocols such as Printable that allows it to be represented as a string. Alternativley perhaps you have something like a name variable inside that is a string

Depending on the version of Swift you are using you could do something like:

extension Formules : Printable {

   override public var description: String {

            return "TEST"
    }
}

but with out more actual code info i can't tell you if this will actually work