将NSManagedObject从一个类传递给Swift编程语言中的其他类？

Question

我有以下的数据库，

我有以下的员工NSManagedObject类。

进口基金会 进口CoreData

class Employee: NSManagedObject { 

    @NSManaged var age: NSNumber 
    @NSManaged var firstName: String 
    @NSManaged var gender: String 
    @NSManaged var lastName: String 
    @NSManaged var salary: NSNumber 

} 

我对其中包含5个UITextFields和一个UIButton的在数据库中添加值UIViewController类。

如果我insertValue在同一个班级，像

let employee:Employee = NSEntityDescription.insertNewObjectForEntityForName("Employee", inManagedObjectContext: self.managedObjectContext!) as Employee 

它工作正常，但我跟对象应用程序的面向结构，并提出了DatabaseManager.swift类，

所以现在发我面临的是将Controller类中的NSManagedObject传递给DatabaseManager类。

我编码如下，但它给错误。

@IBAction func addToDatabase(sender: UIButton) { 
    println("Add to Database is clicked") 

    var employee:Employee = Employee() //Employee is subclass of NSManagedObject 

    employee.firstName = textfield_firstName.text 
    employee.lastName = textfield_lastName.text 
    employee.gender = textfield_gender.text 
    employee.age = (textfield_age.text as String).toInt()! 
    employee.salary = (textfield_salary.text as String).toInt()! 

    var databaseManager:DatabaseManager = DatabaseManager() 
    databaseManager.saveEmployee(employee) 

} 

错误：

2014-11-06 10:34:46.710 CoreDataWithSwift[588:9220] CoreData: error: Failed to call designated initializer on NSManagedObject class 'CoreDataWithSwift.Employee' 
2014-11-06 10:34:46.736 CoreDataWithSwift[588:9220] -[CoreDataWithSwift.Employee setFirstName:]: unrecognized selector sent to instance 0x7fa269e20800 
2014-11-06 10:34:46.756 CoreDataWithSwift[588:9220] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CoreDataWithSwift.Employee setFirstName:]: unrecognized selector sent to instance 0x7fa269e20800' 

感谢。

Answer 1

你不应该直接创建NSManagedObject实例，而是拨打：

var employee = NSEntityDescription.insertNewObjectForEntityForName(entityName, inManagedObjectContext: managedObjectContext) as Employee? 

，然后更改员工的属性并保存结果。