I need to dynamically add properties to an existing class then access them. I found this answer using objc_setAssociatedObject but there’s no context on how to use it. How can I achieve this?

let dict = ["orderId":"abc", "postId+0":"zero", "postId+1":"one", "postId+2":"two"] // postIds can go on

let order = Order(dict: dict)

let dynamicProperties = order.accessDynamicProperties()

print(dynamicProperties)

Class:

class Order {

var orderId: String?

// I have a main initilizer that I use for something else that's why I'm using a convenience init

convenience init(dict: [String: Any]) {

self.init()

orderId = dict["orderId"] as? String

dynamicallyCreateProperties(dict: dict)

}

func dynamicallyCreateProperties(dict: [String: Any]) {

for (key, value) in dict {

if key.contains("+") {

// dynamically add property and value to class

}

}

}

// returns something???

func accessDynamicProperties() -> ??? {

}

}

解决方案

Using the suggestion from @DonMag in the comments he gave me a great alternative. He suggested I create a dictionary as a property on the class then add the key,value pairs to it.

class Order {

var orderId: String?

var dynamicDict = [String: Any]()

convenience init(dict: [String: Any]) {

self.init()

orderId = dict["orderId"] as? String

createDynamicKeyValues(dict: dict)

}

func createDynamicKeyValues(dict: [String: Any]) {

for (key, value) in dict {

if key.contains("+") {

dynamicDict.updateValue(value, forKey: key)

}

}

}

}

To use it:

let dict = ["orderId":"abc", "postId+0":"zero", "postId+1":"one", "postId+2":"two"] // postIds can go on

let order = Order(dict: dict)

for (key, value) in order.dynamicDict {

print(key)

print(value)

}