案例切換中的Swift 3.0 UnsafeMutableRawPointer

Question

以下適用於Swift 3.0：

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?)
    {
        if context == &MyContext1 {
        .........
        }
        else if context == &MyContext2 {
        .........
        }
}

但是，由於我有很多條件，如果我使用這樣的開關/案例：

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?)
    {
        switch context {
           case &MyContext1 :
                ........
           case &MyContext2 :
                ........
        }
    }

我得到一個關於UnsafeMutableRawPointer無法轉換為整數的錯誤。

聲明：

private var MyContext1 = 0
private var MyContext2 = 0

Answer 1

解包context ，代碼編譯正常：

private var MyContext1 = 0
private var MyContext2 = 0

func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    switch context! {
    case &MyContext1 : break
        //
    case &MyContext2 : break
    //
    default: break
    }
}