如何基于LINQ中的类型对集合进行排序 [英] How to sort a collection based on type in LINQ

问题描述

我有一个这样的收藏

Class Base{}
Class A : Base {}
Class B : Base {}

List<Base> collection = new List<Base>();
collection.Add(new A());
collection.Add(new B());
collection.Add(new A());
collection.Add(new A());
collection.Add(new B());

现在，我想根据类型(A/B)对集合进行排序.我该怎么做?请帮助我.

Now I want to sort the collection based on type (A/B). How I can do this? Please help me.

推荐答案

您可以使用类型信息本身:

You can use the type information itself:

collection.Sort( (a,b) => 
  {
      bool aType = a.GetType() == typeof(A);
      bool bType = b.GetType() == typeof(A);
      return aType.CompareTo(bType);
  });

这将适用于您指定的两种类型，但不会超出它们.它确实允许您显式指定顺序(即:如果希望在"A"之前使用"B"元素，则可以使用此技术使其生效).

This will work for the two types you specified, but doesn't scale beyond them. It does allow you to specify the order explicitly (ie: if you want "B" elements before "A", you could make it work using this technique).

如果你需要支持多种类型，并且不需要提前指定排序，你可以这样做:

If you need to support many types, and the ordering doesn't need to be specified in advance, you could do something like:

collection.Sort( (a,b) => a.GetType().FullName.CompareTo(b.GetType().FullName) );

这将处理任意数量的类型(即，也包括C和D子类型)，并按其完整类型名称对其进行排序.

This would handle any number of types (ie: a C and a D subtype, too), and order them by their full type name.

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