c# - 基于内部属性展平集合

Question

给定以下类结构:

int Id;
string[] Codes;

以及以下数据:

Foo { Id = 1, Codes = new[] { "01", "02" } }
Foo { Id = 2, Codes = new[] { "02", "03" } }
Foo { Id = 3, Codes = new[] { "04", "05" } }

我想以以下结构结束。

Code = "01", Id = 1
Code = "02", Id = 1
Code = "02", Id = 2
Code = "03", Id = 2
Code = "04", Id = 3
Code = "05", Id = 3

---

我有以下查询，但它给了我一个集合作为 Id，而不是我所追求的平面结构。

collection.GroupBy(f => f.Codes.SelectMany(c => c), f => f.Id,
      (code, id) => new { Code = code, Id = id })
   .ToArray()

我错过了什么？

Answer 1

SelectMany可以将每个项目的多个元素作为单个列表返回

items
    .SelectMany(foo => foo.Codes.Select(code => new { Id = foo.Id, Code = code }));