Question

我正在尝试使用LINQ：

创建/填充对象MyObject

public class MyObject
{
    public string Title { get; set; }
    public List<Item> Items { get; set; }
}

public class Item
{
    public string Title { get; set; }
    public string Color { get; set; }
    public int Value { get; set; }
}

我有一个DataTable，内容如下：

Title        Color        Value
-----        -----        -----
Something    Green        14
Title 2      Red          7
Title 4      Green        5
More         Green        12
Title 8      Red          6

我将如何进行并按颜色分组创建MyObject？我尝试使用LINQ，我对分组很好，但我不知道如何填充Items：

var groupedObjects = from row in dataTable.AsEnumerable()
                     group row by row.Field<string>("Color")
                     into grp
                     select new MyObject
                     {
                       Name = grp.Key
                       //,Items = this is where I don't know how to continue.
                       //Subselect to get all items where grp.Key == row.Field<string>("Color")?
                     };

我的最终结果应该是这样的（JSON，我想这会是List<MyObject>）：

{
  "Title" : "Green",
  "Items": [
      {
        "Title" : "Something",
        "Color" : "Green",
        "Value" : 14
      },
      {
        "Title" : "Title 4",
        "Color" : "Green",
        "Value" : 5
      }
    ],
  "Title" : "Red",
  "Items": [
      {
        "Title" : "Title 2",
        "Color" : "Red",
        "Value" : 7
      },
      {
        "Title" : "Title 8",
        "Color" : "Red",
        "Value" : 6
      }
    ]
}

Answer 1

您已经拥有这些群组，因此您只需要在群组中投放项目并将其转换为项目，您就不需要额外的过滤：

var groupedObjects = from row in dataTable.AsEnumerable()
                 group row by row.Field<string>("Color")
                 into grp
                 select new MyObject
                 {
                    Name = grp.Key,
                    Items = grp.Select(x => new Item 
                                            { 
                                               Title = x.Field<string>("Title"),
                                               Color = x.Field<string>("Color"), 
                                               Value = x.Field<int>("Value")
                                            }).ToList()
                 };

Linq group by with subselect of grouped items

1 个答案: