实例成员不能用于类型

Question

@IBAction func saveDetails(sender: AnyObject) {
        Person.firstName = firstNameTF.text
        Person.lastName = lastNameTF.text
}

上面是我要实现的功能，下面是 class 我正在尝试创建一个实例并将我的文本字段中的数据存储在...我收到错误 "Instance member "firstName" 不能用于 Person" 类型。我几乎确定我的 class 已正确设置和初始化，所以我看不出问题出在哪里？

class Person {
    var firstName : String = ""
    var middleName : String? = nil
    var lastName : String = ""
    var yearOfBirth : Int? = nil
    var age : Int! {
        get {
            guard let _ = yearOfBirth else {
                return nil
            }
            return currentYear - yearOfBirth!
        }
        set {
            yearOfBirth = currentYear - newValue
        }
    }

    init(firstName: String, lastName: String, yearOfBirth: Int? = nil, middleName: String? = nil){
        self.firstName = firstName
        self.lastName = lastName
        self.yearOfBirth = yearOfBirth
        self.middleName = middleName
    }
    convenience init(firstName: String, lastName: String, age: Int, middleName: String? = nil) {
        self.init(firstName: firstName, lastName: lastName, yearOfBirth: nil, middleName: middleName)
        self.age = age
    }

}

Answer 1

"Instance member "firstName“不能用于 Person 类型”是完美的解释。

class C {
    var s: String = ""
    static var s1: String = ""
}


C.s1 = "alfa"
//C.s = "alfa" //  error: instance member 's' cannot be used on type 'C'
let c0 = C()
c0.s = "beta"
//c0.s1 = "beta" // error: static member 's1' cannot be used on instance of type 'C'

Answer 2

您应该创建一个 Person 实例以设置其属性：要么这样做：

@IBAction func saveDetails(sender: AnyObject) {
    let p = Person(firstName: firstNameTF.text!, lastName: lastNameTF.text!)
}

或者添加一个不接受参数的 init 方法给你的 Person class

@IBAction func saveDetails(sender: AnyObject) {
    let p = Person()
    p.firstName = firstNameTF.text!
    p.lastName = lastNameTF.text!
}

Answer 3

错误消息说您无法调用 class（类型）Person.

上的属性

使用给定的初始值设定项

创建一个Person实例

@IBAction func saveDetails(sender: AnyObject) {
   let person = Person(firstName:firstNameTF.text, lastName:lastNameTF.text)
   // do something with person
}

实例成员不能用于类型

Instance member cannot be use on type

xcode

swift

xcode7

swift2