迁移期间无法将类型 'RealmSwift.DynamicObject' 的值转换为 MyCustomObject

Question

在 RealmSwift migration 期间，我想从 dynamic var customObject: CustomObject 迁移到 let customObjectList = List<CustomObject>()。 CustomObject 是 Object

的类型

这是迁移中的代码块

let newList = List<CustomObject>()
if oldObject!["customObject"] != nil {

   print(oldObject!["customObject"])                  
   var obj = oldObject!["customObject"]
   var result: CustomObject = obj as! CustomObject //Crash
   farList.append(result)
}

newObject!["customObjectList"] = newList

Could not cast value of type 'RealmSwift.DynamicObject' (0x1015c82d0) to 'AppName.CustomObject' (0x1006e5550).

我如何实现我想要的？目前我能想到的是创建一个 CustomObject 并手动为其分配值。

编辑 1

我想给 CustomObject 添加一个主键。我不断收到重复的主键错误，我很确定分配的键是唯一的。

fatal error: 'try!' expression unexpectedly raised an error: Error Domain=io.realm Code=0 "Primary key property 'resultKey' has duplicate values after migration."

 migration.deleteData(CustomObject.className())

 if oldObject!["customObject"] != nil {
          let oldSubFar = oldObject!["customObject"] as! MigrationObject
          var newFarDict = oldSubFar.dictionaryWithValuesForKeys(["firstName","secondName"])
          newFarDict["resultKey"] = NSUUID().UUIDString + "v1"


          let newSubFar = migration.create(CustomObject.className(), value: newFarDict )
          print(newSubFar) //its the updated object that i want
          let subFarList = newObject!["customObjectList"] as! List<MigrationObject>         

          subFarList.append(newSubFar)               

 }

编辑 2

I manage to figure out what is the error by making resultKey not a primary key. The app runs perfectly and when i open .realm to see the values, there are some fields with "" under resultKey -> The duplicated primary key. ><

Answer 1

我想你想做的是：

如果需要，删除所有 CustomObject 数据，因为迁移列表对象无法附加现有对象。

然后您可以枚举 User 个对象，并从 User 的属性创建每个 CustomObject。并且新的 User 对象有 customObject 属性，然后将 CustomObject 对象添加到列表中。

migration.deleteData(CustomObject.className()) // If needed

migration.enumerate(User.className()) { oldObject, newObject in
    if let oldObject = oldObject,
        let newObject = newObject {
            let oldCustomObject = oldObject["customObject"] as! MigrationObject
            let newCustomObject = migration.create(CustomObject.className(), value: oldCustomObject)

            let customObjectList = newObject["customObjectList"] as! List<MigrationObject>
            customObjectList.append(newCustomObject)
    }
}

迁移期间无法将类型 'RealmSwift.DynamicObject' 的值转换为 MyCustomObject

Could not cast value of type 'RealmSwift.DynamicObject' to MyCustomObject during migration

realm

realm-migration

xcode7

swift2