LINQ - 组特定类型的类 [英] LINQ - group specific types of classes

问题描述

这个问题类似于<一href="http://stackoverflow.com/questions/2835192/linq-group-one-type-of-item">http://stackoverflow.com/questions/2835192/linq-group-one-type-of-item但在一个更通用的方法来处理。

This question is similar to http://stackoverflow.com/questions/2835192/linq-group-one-type-of-item but handled in a more generic way.

我有一个列表，具有多种派生类。我可能有这样的事情：

I have a List that has various derived classes. I may have something like this:

List<BaseClass> list = new List<BaseClass>() {
  new Class1(1),
  new Class2(1),
  new Class1(2),
  new Class3(1),
  new Class2(2),
  new Class4(1),
  new Class3(2)
};

我想使用LINQ到半排序列表，以便自然秩序维持，除了某些类具有base.GroupThisType ==真。所有类与GroupThisType应在该第一类的相同类型的发生地组合在一起。以下是输出应该是这样的：

I am trying to use LINQ to semi-sort the list so that the natural order is maintained EXCEPT for certain classes which have base.GroupThisType == true. All classes with GroupThisType should be grouped together at the place that the first class of the same type occurs. Here is what the output should be like:

List<BaseClass> list = new List<BaseClass>() {
  new Class1(1),
  new Class1(2),
  new Class2(1),
  new Class3(1),
  new Class3(2)
  new Class2(2),
  new Class4(1),
};

编辑：哎呀，忘了说这个结果是假设（1类和3类）.GroupThisType ==真

Oops, forgot to say this result is assuming (Class1 and Class3).GroupThisType == true

推荐答案

这样的：

list = list.Select((o, i) => new { Index = i * 10000, Value = o })
           .GroupBy(q => q.GetType())
           .SelectMany(g => {
               if (g.First().GroupThisType)
                   return g.Select((q, i) => 
                       new { Index = g.First().Index + i, Value = q.Value }
                   );
               else
                   return g;
           })
           .OrderBy(q => q.Index)
           .Select(q => q.Value)
           .ToList();

在 I * 10000 允许多达10,000项从一组被任何两个项目之间插入。

The i * 10000 allows up to 10,000 items from a group to be inserted between any two items.

您可以替换 g.First（）。GroupThisType 与 typesToGroup.Contains（g.Key）。

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