Question

我在详细视图控制器中创建新的子实体。所以我发送了segue

detailedViewController.managedObjectContext = managedObjectContext;
detaledViewController.parent = currentParent; //type of Parent

在detailViewController.m

-(IBAction)saveChildObj:(id)sender{
  self.childEntity= [NSEntityDescription insertNewObjectForEntityForName:@"ChildEntity" inManagedObjectContext:self.managedObjectContext];
        self.childEntity.childEntityName= self.childEntityName.text;

        [self.parent addMyChildObject:self.childEntity];
        [self.managedObjectContext performBlockAndWait:^{
            NSError *error = nil;
            BOOL saved = [self.managedObjectContext save:&error];
            if (!saved) {
                // do some real error handling
                NSLog(@"Could not save Date due to %@", error);
            }
            [[osCoreDataController sharedImstanse] saveMasterContext];
        }];


        [self.navigationController popViewControllerAnimated:YES];

}

调用addMyChildEntity后，我的文本错误：

2013-06-09 22:21:39.191 FindYourMedicine[2476:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Illegal attempt to establish a relationship 'parent' between objects in different contexts (source = <ChildEntity: 0x8acbf30> (entity: ChildEntity; id: 0x8accb10 <x-coredata:///ChildEntity/t8DB5D204-A359-45E5-8F2B-8DE6A26D245C3> ; data: {
    date =     (
    );
    parent= nil;
    childEntityName= fgh;
    times =     (
    );
}) , destination = <Parent: 0x8a9a9a0> (entity: Parent; id: 0x8a99cb0 <x-coredata://48BBE637-9D07-4529-9C6A-DCCF118B4717/Disease/p2> ; data: {
    parentName = "\U0430\U0441\U0442\U043c\U0430";
    childEntity=  (

）;

核心数据的结构对很多人来说是：父母 - ＆gt;＆gt;儿童 - ＆gt;＆gt;次

我尝试使用managedObjectContext.parantContext但没有任何帮助

Answer 1

不要传递托管对象上下文，只需传递父对象。然后，当您需要添加子项时，只需向父项询问其托管对象上下文（所有托管对象都具有此属性）。

使用正确的托管对象上下文添加子实体

1 个答案: