iOS – 如果找到匹配,则更新托管对象

在获取我想要修改的对象后,我似乎无法弄清楚如何更新核心数据对象.

这就是我想要做的:

1)从核心数据匹配谓词条件中查找第一个对象:

NSInteger storeId = 235;  //find object with this id in core data

NSManagedObjectContext *context = [[NSManagedObjectContext alloc] init];
[context setPersistentStoreCoordinator:[self.managedObjectContext persistentStoreCoordinator]];

NSFetchRequest *request = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Store"
                                          inManagedObjectContext:context];
[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"id == %i",storeId];
[request setPredicate:predicate];

NSArray *results = [context executeFetchRequest:request error:NULL];

2)如果找到匹配,更新匹配对象(这是我需要帮助的地方):

if (results != nil && [results count] > 0)
{
    /** Not sure how to get the correct context and modify object **/

    Store *matchingObject = [results objectAtIndex:0];
    [context setValue:[NSNumber numberWithInteger:storeId] forKey:"id"];
}


/** Save the context */
NSError *error = nil;
if (![context save:&error]) {     
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        //abort();
}

感谢您提供任何帮助…

最佳答案 尝试直接修改对象属性并保存它:

matchingObject.id = [NSNumber numberWithInteger:storeId];

该对象最初是使用上下文获取的,因此您应该可以通过调用上下文保存来保存更改.

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