在具有跨越多个实体的Core Data绑定的Cocoa中实现parent>子查询 [英] Implementing parent->child drill down in Cocoa with Core Data bindings that span multiple entities

问题描述

我尝试以iTunes类型浏览器的风格为我的核心数据模型创建一个简单的界面。

I'm trying to create a simple interface to my core data model in the style of iTunes Genre browser.

我有一个模型设置，有三个实体： code> Genre< - >>艺术家< - >>

I have a model setup with three entities: Genre <-->> Artist <-->> Album.

我想简单地将它们绑定到一个NSTableView，但它看起来好像访问儿童关系从一个NSArrayController不是KVC兼容。因此，我无法将所选的Genre对象传递给ArtistController。

I'd like to simply tie them each to a NSTableView, but it appears as though accessing children relationships from a NSArrayController is not KVC compliant. So, I'm having difficulty communicating the selected Genre objects to the ArtistController.

如何做到这一点？

编辑Posterity：我做错了几个错误。

• 子控制器需要通过自己的绑定知道managedObjectContext。


• 子控制器必须位于 Entity 模式中，而是作为 NSMutableDictionary 类进行操作。


• 最后，子控制器不准备其数据。它通过内容集绑定从父级检索它。使用控制器键 selection ，以及连接到子项的模型键路径。

• The child controller needs to know about the managedObjectContext through its own binding.
• The child controller must not be in Entity Mode, but rather operate as a NSMutableDictionary class.
• And, finally, the child controller does not prepare its data. It retrieves it from the parent, through the Content Set binding. Use the controller key selection, and the model key path that connects to the children.

phew 。 Brian的答案和此MacResearch教程

phew. Both Brian's answer and this MacResearch tutorial were helpful in determining my errors (and which parts I had right).

推荐答案

我可能会采取的方法是一个单独的NSArrayController为每个表视图，然后有一个数组控制器的内容基于另一个选择。

The approach I would probably take is to have a separate NSArrayController for each table view, then have the content of one array controller be based on the selection of another.

例如，你有表视图A显示可用流派的列表，所以它有一个数组控制器A的内容被挂接到您的托管对象上下文。

For example, say you have table view A that displays the list of available genres, so it has an array controller A whose content is hooked up to your managed object context.

然后，假设您有表视图B，其中显示了表A中选择的任何类型的可用艺术家。此表将有自己的数组控制器B，控制器B的数组被绑定，因此IB中的控制器键字段被设置为控制器A的选择键，其中艺术家是模型键（这假设您的类型实体具有名为艺术家到艺术家实体）。

Then, say you have table view B which shows the available artists for whichever genre is selected in table A. This table would have its own array controller B, and the content array for controller B is bound so the "controller key" field in IB is set to the "selection" key of controller A, with "artists" being the model key (this assumes your Genre entity has a to-many relationship named "artists" to the Artist entity).

然后，您可以将同样的原理应用到第三个表格视图+控制器，以显示所选艺术家的相册。

You can then apply the same principle to a third table view + controller to show the albums for the selected artist.

这种设置的通用术语是主 - 细节界面，并在Apple的文档此链接

The general term for this kind of setup is a "master-detail interface", and is outlined in Apple's docs at this link

这篇关于在具有跨越多个实体的Core Data绑定的Cocoa中实现parent&gt;子查询的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！