为什么以及何时继承Collection& lt; T& gt; [英] Why and when to inherit from Collection<T>
问题描述
我正在用C#编写的项目中跟踪遗留代码.
I'm tracing legacy code in my project written in C#.
我找到以下代码:
public class FooCollection : Collection<IFoo> {};
我不明白为什么(和何时)需要创建这样的Collection类.
I don't understand why (and when) we need to create our own Collection class like this.
为什么不只使用内置集合( array ， List< T> ， Dictionary< K，V> ，..)
Why not just use the build-in collection (array, List<T>, Dictionary<K,V>, ...)
Collection< T> 中使用的数据结构是什么?大批?或链表?
What's the data structure used in Collection<T> ?? array? or linked list?
推荐答案
我不明白为什么(和何时)需要创建这样的Collection类.
I don't understand why (and when) we need to create our own Collection class like this.
您并不是真的需要"；您可以直接直接使用 Collection< IFoo> ，但是拥有特定的类可以提高可读性.
You don't really "need" to; you could just use Collection<IFoo> directly, but having a specific class can help readability.
此外，它允许您为此集合类型添加特定的行为，因为 Collection< T> 类允许通过重写虚拟方法来重新定义大多数操作；这使您可以自定义标准收集方法的行为.
Also, it allows you to add specific behavior for this collection type as the Collection<T> class allows most operations to be redefined by overriding virtual methods; this allows you to customize the behavior of the standard collection methods.
因此，例如，当您不能直接覆盖 Add 方法时，可以覆盖 InsertItem ，然后由 Add ， AddRange 等.
So, for example, while you cannot directly override the Add method, you can override InsertItem which is then used by Add, AddRange etc.
为什么不只使用内置集合(数组，列表，字典等)
Why not just use the build-in collection (array, List, Dictionary, ...)
数组的长度是固定的，因此您不能添加或删除项目.所以这不是真正的等价物. Dictionary< K，V> 将值与键相关联，因此它具有明显不同的用途.只要您不需要自定义行为，就可以使用 List< T> 来代替.此类不是为继承而设计的，因为它的方法是非虚拟的.
An array has a fixed length, so you can't add or remove items; so it's not really equivalent. Dictionary<K,V> associates a value with a key, so it has a clearly different purpose. List<T> could be used instead, as long as you don't need to customize the behavior; this class is not designed for inheritance, since its methods are non-virtual.
Collection中使用的数据结构是什么?大批?或链表?
What's the data structure used in Collection ?? array? or linked list?
Collection< T> 充当另一个 IList< T> 的包装.默认情况下，它使用 List< T> (基于数组)，但是您可以将任何其他 IList< T> 实现传递给构造函数，并且它会改用它.
Collection<T> acts as a wrapper around another IList<T>. By default, it uses a List<T> (which is based on an array), but you can pass any other IList<T> implementation to the constructor, and it will use that instead.
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