仅适用于iOS 10的Swift 3中的NSBatchDeleteRequest？ [英] NSBatchDeleteRequest in Swift 3 for iOS 10 only?

问题描述

所以，将我的代码迁移到 Swift 3 让我有点卡住了。似乎 NSBatchDeleteRequest 现在要求 iOS 10 ？我可以进行代码构建的唯一方法是使用以下代码段：

So, migrating my code to Swift 3 has me a bit stuck. It seems NSBatchDeleteRequest requires iOS 10 now? The only way I could make the code build is with the following snippet:

func removeAllChargerData(){
    // Remove all charging data from persistent storage
    let fetchRequest: NSFetchRequest<NSFetchRequestResult> = ChargerPrimary.fetchRequest()
    let entity = NSEntityDescription.entity(forEntityName: "ChargerPrimary", in: self.secondMoc)
    fetchRequest.entity = entity
    let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)

    do {
        try self.secondMoc.execute(deleteRequest)
    } catch {
        let deleteError = error as NSError
        NSLog("\(deleteError), \(deleteError.localizedDescription)")
    }

}

然而，出现警告，表明 fetchRequest（）仅在 iOS 10 中可用，并且新。如果我按以下方式定义 fetchRequest ，则会出现错误，因为它希望 fetchRequest 具有 NSFetchRequestResult 参数类型：

However, a warning shows up indicating that fetchRequest() is only available in iOS 10 and newer. If I define the fetchRequest the following way, I get an error because it expect the fetchRequest to has a NSFetchRequestResult argument type:

let fetchRequest = NSFetchRequest<ChargerPrimary>(entityName: "ChargerPrimary")

推荐答案

您只需指定正确的类型通用：

You just need to specify the correct type for the generic:

let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ChargerPrimary")

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