SwiftUI - Core-Data - 在这种特殊情况下访问包装的值

Posted 2023-03-05

【中文标题】SwiftUI - Core-Data - 在这种特殊情况下访问包装的值

【英文标题】：SwiftUI - Core-Data - Access to wrapped value in this kind of special case

【发布时间】：2020-09-07 17:02:35

【问题描述】：

使用下面的代码（见下面的代码），我得到了这种结果（见下面的结果）： 从下面显示的代码开始（不使用视图...），我怎样才能访问 WrappedValues 而不是这种结果？

感谢您的帮助！

结果：

<Translation: 0x600002132440> (entity: Translation; id: 0x6742c7fbe17c81d1 <x-coredata://0B558EF2-1CC5-4649-9D70-560DAA900FFE/Translation/p21>; data: 
    id = 11;
    language = English;
    wording = "Select the Folders to Rename...";
)

代码：

class FetchWording: ObservableObject 
    func fetch (pID: String) -> String 
        let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Translation")
        fetchRequest.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [NSPredicate(format: "id == %@", pID as CVarArg), NSPredicate(format: "language == %@", sDisplayLanguage as CVarArg)])
        fetchRequest.fetchLimit = 1
         do 
            let fetchWording = try ContentView().managedObjectContext.fetch(fetchRequest)
            print (fetchWording[0])
          catch 
             print ("Error")
         
        return (“See you later when it’s working”)
    

【参考方案1】：

…随便找这个，不是很满意：

    let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Translation")
    fetchRequest.predicate = NSCompoundPredicate(andPredicateWithSubpredicates: [NSPredicate(format: "id == %@", pID as CVarArg), NSPredicate(format: "language == %@", sDisplayLanguage as CVarArg)])
    fetchRequest.fetchLimit = 1
    var fetchWording = [NSManagedObject]()
    do 
        let records = try ContentView().managedObjectContext.fetch(fetchRequest)

        if let records = records as? [NSManagedObject] 
            fetchWording = records
        
        return **fetchWording.first!.value(forKey: "wording")! as! String**
     catch 
        print ("Unexpected error: Function fetch: Wording not found!")