如何在 Swift 中将 NSDateComponents 转换为 DateComponents

Question

I want to conver NSDateComponents to DateComponents. How can I do it in Swift without force casting.

Answer 1

There is nothing to convert. Just use DateComponents wherever you would previously have used NSDateComponents.

(You can in fact cast from one to the other using as , but you will never need to. Your code should contain no reference to NSDateComponents in Swift 3. You use DateComponents instead .)

Answer 2

As a addition to why the question is valid and and an example of why:

Not all APIs are yet converted to DateComponents. One example is the Contact framework where the instance property dates of the CNContact/CNMutableContact classes is declared as

open var dates: [CNLabeledValue<NSDateComponents>]

Unfortunately there is no built-in way to convert between the two so if you want to avoid force casting you will have to set each property your self:

nsDateComponents.day = dateComponents.day
nsDateComponents.month = dateComponents.month
// etc ...

Be aware that it is not a 1:1 mapping of the properties of the two classes, you will have to look up the API if you want to do a complete mapping.