在初始化之后，如何将NSManagedObject与上下文相关联？ [英] How can I associate an NSManagedObject to the context after it has been initialised?

问题描述

例如，如果我有一个 NSManagedObject 名为 Items ，并且我想设置 ManagedObjectContext 以后（不是初始化时），我该怎么做？

>

  Items * item = [NSEntityDescription insertNewObjectForEntityForName：@Items
 inManagedObjectContext：_context]; 
  

自动将其与 _context 关联。 / p>

但是如果我想这样做呢？

  = [[Items alloc] init]; 
 item.first = @bla; 
 item.second = @bla bla; 
  

而我想将该对象传递给另一个方法，然后将其与上下文相关联并保存

所以有办法做一个简单的 item.managedObjectContext = _context 或类似的东西吗？

解决方案

这种方法完全有效...

  Items * item = [[Item alloc] initWithEntity：entity insertIntoManagedObjectContext：nil]; 
 item.first = @blah; 
 item.second = @blah blah; 
  

然后，您可以自由地将此对象传递到需要的位置，将其提交到受管对象上下文，只需插入它并保存。

  [managedObjectContext insertObject：item]; 
 NSError * error = nil; 
 [managedObjectContext save：& error]; 
  

For example, if I have an NSManagedObject named Items, and I want to set the ManagedObjectContext later (not when initialised), how would I do that?

At the moment I'm doing this:

Items *item = [NSEntityDescription insertNewObjectForEntityForName:@"Items" 
                                                inManagedObjectContext:_context];

That automatically associates it to _context.

But what if I want to do this:

Items *item = [[Items alloc] init];
item.first = @"bla";
item.second = @"bla bla";

And I would want to pass that object to another method which would then associate it with the context and save it.

So is there any way to just do a simple item.managedObjectContext = _context or something like that?

解决方案

This approach would be perfectly valid...

Items *item = [[Item alloc] initWithEntity:entity insertIntoManagedObjectContext:nil];
item.first = @"blah";
item.second = @"blah blah";

You're then free to pass this object around to where its needed and when you're ready to commit it to a managed object context, simply insert it and save.

[managedObjectContext insertObject:item];
NSError *error = nil;
[managedObjectContext save:&error];

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