Swift 函数返回对象'；s属性

我想更改对象的参数，但我想稍后决定应该更改哪些参数。我想做一个函数，但不知道怎么做。以下是一个示例：

class Car {
    var color = "green"
    var brand = "Zastava"
    var mechanic = "Mark Gaia"
}

struct Change {
    var property: String
    var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.propertyFromChange(change) = change.newValue  // ??? How to implement this line

如何使函数返回需要更改的对象的参数是什么？
或者，如何选择要更改的参数？
（…我考虑了

switch

语句。这是一个好的方向吗？）

---

我很确定这是互联网上已经讨论过的事情。我已经阅读了有关函数的所有内容，但找不到解决方案，因此我猜我使用了错误的关键字进行搜索。

您不需要创建一个函数。您可以在继承自

NSObject

后这样使用KVC，也可以创建一个新的函数，再次保护坏的属性名

class Car: NSObject {
    var color = "green"
    var brand = "Zastava"
    var mechanic = "Mark Gaia"
}

struct Change {
    var property: String
    var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

请记住，如果输入错误的属性名称，此代码将崩溃

class Car: NSObject {
    var color = "green"
    var brand = "Zastava"
    var mechanic = "Mark Gaia"
}

struct Change {
    var property: String
    var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

---

希望这能回答您的问题。

您不需要创建一个函数，您可以在继承自

NSObject

后像这样使用KVC，也可以创建一个新的函数，再次保护坏的属性名

class Car: NSObject {
    var color = "green"
    var brand = "Zastava"
    var mechanic = "Mark Gaia"
}

struct Change {
    var property: String
    var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

请记住，如果输入错误的属性名称，此代码将崩溃

class Car: NSObject {
    var color = "green"
    var brand = "Zastava"
    var mechanic = "Mark Gaia"
}

struct Change {
    var property: String
    var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

---

希望这能回答您的问题。

您可以通过将

Car

作为

NSObject

的子类，利用KVC

setValue（value:AnyObject？，forKey:String）

方法

class Car: NSObject {
  var color = "green"
  var brand = "Zastava"
  var mechanic = "Mark Gaia"
}

struct Change {
  var property: String
  var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")

car.setValue(change.newValue, forKey: change.property)

---

通过使

Car

成为

NSObject

的子类，可以利用KVC

setValue（value:AnyObject？，forKey:String）

方法

class Car: NSObject {
  var color = "green"
  var brand = "Zastava"
  var mechanic = "Mark Gaia"
}

struct Change {
  var property: String
  var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")

car.setValue(change.newValue, forKey: change.property)

---

如果

Car

继承自

NSObject

您可以免费获得键值编码，并可以使用

setValue:forKey更改值

class Car : NSObject {
  var color = "green"
  var brand = "Zastava"
  var mechanic = "Mark Gaia"
}

struct Change {
  var property: String
  var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

如果
Car
继承自
NSObject
您可以免费获得键值编码，并可以使用
setValue:forKey更改值

class Car : NSObject {
  var color = "green"
  var brand = "Zastava"
  var mechanic = "Mark Gaia"
}

struct Change {
  var property: String
  var newValue: String
}

let car = Car()
let change = Change(property: "brand", newValue: "Fiat")
car.setValue(change.newValue, forKey: change.property)

通过这样做，您可以稍微简化您的方法

如果将所有属性存储在结构本身中，则根本不需要担心这一点

希望这能有所帮助

    struct CarProperties {
    var color : String = ""
    var brand : String = ""
    var mechanic : String = ""
}
class Car {
    var carProperties = CarProperties()
}

let car = Car()
car.carProperties.color = "Green"
car.carProperties.brand = "yourFavBrand"
car.carProperties.mechanic = "whatever"

let change = "this"

// Suppose you want to change the  brand
car.carProperties.brand = change

print(car.carProperties.brand)

通过这样做，您可以稍微简化您的方法

如果将所有属性存储在结构本身中，则根本不需要担心这一点

希望这能有所帮助

    struct CarProperties {
    var color : String = ""
    var brand : String = ""
    var mechanic : String = ""
}
class Car {
    var carProperties = CarProperties()
}

let car = Car()
car.carProperties.color = "Green"
car.carProperties.brand = "yourFavBrand"
car.carProperties.mechanic = "whatever"

let change = "this"

// Suppose you want to change the  brand
car.carProperties.brand = change

print(car.carProperties.brand)