当添加关系对象w/ core data时，获取“无法在正向类对象中找到属性”错误

I have a core data model with four entities. The entity Player has a to-Many relationship to the other entities (Player_Scores,Custom_Exercise,Selected_Exercise).

我有一个包含四个实体的核心数据模型。实体播放器与其他实体有很多关系(player_score,Custom_Exercise,Selected_Exercise)。

In my app delegate, I make NSManagedObjectContext,NSManagedObjectModel,NSPersistentStoreCoordinator properties in the standard way. Then, in a different view controller, I declare ivars for an NSManagedObjectContext object and a newPlayer Player entity in the @interface:

在我的app委托中，我用标准的方式创建NSManagedObjectContext NSManagedObjectModel NSPersistentStoreCoordinator属性。然后，在另一个视图控制器中，我在@interface中为NSManagedObjectContext对象和newPlayer播放器实体声明ivars:

@interface NewProfileViewController()
{
    NSManagedObjectContext *context;
    Player *newPlayer;
}

Then in an action I have the following code to create a Player entity and enter in its attributes, as well as a Player_Scores entity and a Selected_Exercise entity. The code i use successfully adds the attributes for the Player_Scores and the Player entities. However when I try to add 16 Selected_Exercise entities in a loop and set their attributes I get a big fat "Property cannot be found on forward class object?" error. HELP!!!!! Like i said the code is the same for Selected_Exercise and for Player_Scores. I already tried re-starting, deleting database, etc. It's a compiler error that pops up when i try to do newEx.exercise=@"blahblahblah"; or newEx.suit=@"blahblahblah"; UGH

然后在操作中，我有以下代码来创建一个Player实体并输入其属性，以及player_score实体和Selected_Exercise实体。我使用的代码成功地添加了player_score和Player实体的属性。但是，当我尝试在循环中添加16个Selected_Exercise实体并设置它们的属性时，我得到一个大的fat“属性在forward类对象上找不到”错误。救命! ! ! ! !如我所说，Selected_Exercise和player_score的代码是相同的。我已经尝试重新启动、删除数据库等。当我尝试执行newEx.exercise=@“blahblahblahblah”时，会弹出一个编译错误;或newEx.suit = @“blahblahblah”;啊

Below is my code for that method:

下面是我的方法代码:

     //1. save a person to database
        newPlayer=[NSEntityDescription
                           insertNewObjectForEntityForName:@"Player"
                           inManagedObjectContext:context];

        newPlayer.name=newentry;
        //NSError *error; [context save:&error];

        //2. begin making a score card:
        Player_Scores *newScoreCard = [NSEntityDescription
                               insertNewObjectForEntityForName:@"Player_Scores"
                               inManagedObjectContext:context];

        newScoreCard.date_of_game = [NSDate date];
        newScoreCard.player=newPlayer; //attach this score card to the new playe
        [newPlayer addScoresObject:newScoreCard];//add the score card to the newplayer
        //3.  make selected_exercise

        NSString *plistCatPath = [[NSBundle mainBundle] pathForResource:@"ListOfExercises" ofType:@"plist"]; //grab plist
        NSMutableArray* theDictArray= [[NSMutableArray arrayWithContentsOfFile:plistCatPath] copy];

        for(int cnt=0;cnt<[theDictArray count];cnt++){

            Selected_Exercise *newEx= [NSEntityDescription
                                       insertNewObjectForEntityForName:@"Selected_Exercise"
                                       inManagedObjectContext:context];
            newEx.exercise=[[theDictArray objectAtIndex:cnt]valueForKey:@"exercise"];
            newEx.suit=[[theDictArray objectAtIndex:cnt]valueForKey:@"suit"];
            [newPlayer addSelected_exerciseObject:newEx];
            NSLog(@"added exercise %@ for suit %@ at array index %d",[[theDictArray objectAtIndex:cnt]valueForKey:@"exercise"],[[theDictArray objectAtIndex:cnt]valueForKey:@"suit"],cnt);
        }
    // Save everything
    NSError *error = nil;
    if ([context save:&error]) {
        NSLog(@"The save was successful!");
    } else {
        NSLog(@"The save wasn't successful: %@", [error userInfo]);
    }

1 个解决方案

#1

That sounds as if you imported "Player.h", but not "Selected_Exercise.h" in that file.

听起来好像你导入了“播放器”。h”,但不是“Selected_Exercise。h”文件。

"Player.h" probably contains the forward declaration @class Selected_Exercise, so that the compiler does not complain on

”的球员。h“可能包含转发声明@class Selected_Exercise，这样编译器就不会抱怨了

Selected_Exercise *newEx = [NSEntityDescription ...

But if "Selected_Exercise.h" is not imported, the properties of that class, such as newEx.exercise, are unknown to the compiler.

但如果“Selected_Exercise。不导入h"，该类的属性，如newEx。练习，编译器不知道。

#1