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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).

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:

@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

Below is my code for that method:

     //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]);
    }
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1 回答 1

5

听起来好像您在该文件中导入了“Player.h”，而不是“Selected_Exercise.h”。

“Player.h”可能包含前向声明@class Selected_Exercise，因此编译器不会抱怨

Selected_Exercise *newEx = [NSEntityDescription ...

newEx.exercise但是，如果没有导入“Selected_Exercise.h” ，则编译器不知道该类的属性，例如 。

于 2013-04-18T06:54:58.573 回答