Swift 2 ( executeFetchRequest ) : error handling

Question

I got some issue with the code that I can\'t figure out. After I installed Xcode 7 beta and convert my swift code to Swift 2

Code:

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Answer 1

As of Swift 2, Cocoa methods that produce errors are translated to Swift functions that throw an error.

Instead of an optional return value and an error parameter as in Swift 1.x:

var error : NSError?
if let result = context.executeFetchRequest(request, error: &error) {
    // success ...
    list = result
} else {
    // failure
    println("Fetch failed: \(error!.localizedDescription)")
}

in Swift 2 the method now returns a non-optional and throws an error in the error case, which must be handled with try-catch:

do {
    list = try context.executeFetchRequest(request)
    // success ...
} catch let error as NSError {
    // failure
    print("Fetch failed: \(error.localizedDescription)")
}

For more information, see "Error Handling" in "Adopting Cocoa Design Patterns" in the "Using Swift with Cocoa and Objective-C" documentation.

Answer 2

Swift 3.0 In this example PlayerList is NSManagedObject entity/class name (auto created by Xcode)

let request: NSFetchRequest<PlayerList> = PlayerList.fetchRequest()

var result:[PlayerList]?
do{
      //Succes 
      result = try context.fetch(request)
   }catch let error as NSError {
      //Error 
      print("Error \(error)")
  }

print("result: \(result)")

Answer 3

You could try this code:

let  result = (try! self.manageContext.executeFetchRequest(FetchRequest)) as! [NSManageObjectClass]

Answer 4

Try the code below

 override func viewWillAppear(animated: Bool) {

        let appDel:AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)
        let context = appDel.managedObjectContext
        let request = NSFetchRequest(entityName:"Users")
        do {
            let results = try context.executeFetchRequest(request)

            itemList = results as! [NSManagedObject]


        } catch let error as NSError {
            print("Could not fetch \(error), \(error.userInfo)")
        }


    }

Answer 5

var results = [YourEntity]?
results = try! self.managedObjectContext!.executeFetchRequest(fetchRequest) as! [YourEntity]