c# - 如何在linq中将树展平到表中

Question

我有一个列表:

List<DataBanerModel> banerData = new List<DataBanerModel>();
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 1, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 1, Box = 2 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 1, Box = 3 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 2, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 2, Box = 2 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 2, Box = 3 });
banerData.Add(new DataBanerModel { Shop = 1, Cartoon = 3, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 2, Cartoon = 1, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 2, Cartoon = 1, Box = 2 });
banerData.Add(new DataBanerModel { Shop = 2, Cartoon = 1, Box = 3 });
banerData.Add(new DataBanerModel { Shop = 3, Cartoon = 1, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 3, Cartoon = 1, Box = 2 });
banerData.Add(new DataBanerModel { Shop = 3, Cartoon = 1, Box = 3 });
banerData.Add(new DataBanerModel { Shop = 3, Cartoon = 2, Box = 1 });
banerData.Add(new DataBanerModel { Shop = 3, Cartoon = 2, Box = 2 });

我得数一数有多少Box es 将在 Cartoon 中s 和多少 Cartoon s 将在 Shop ，所以结果应该是这样的:

Shop: 1, Cartoons: 3, Boxes: 3
Shop: 1, Cartoons: 3, Boxes: 3
Shop: 1, Cartoons: 3, Boxes: 1
Shop: 2, Cartoons: 1, Boxes: 3
Shop: 3, Cartoons: 2, Boxes: 3
Shop: 3, Cartoons: 2, Boxes: 2

到目前为止我写道:

var step4 = banerData.GroupBy(x => x.Shop)
    .Select(s => new
    {
        Shops = s.Key,
        Cartoons = s.GroupBy(y => y.Cartoon)
            .Select(k => new
            {
                k.Key,
                Boxes = k.GroupBy(z => z.Box)
                .Select(p => p.Key).ToList()
            }).ToList()
        }).ToList();

它工作正常，但我不知道如何压平这棵树。

Answer 1

你可以使用:

  var grouped = banerData
    .GroupBy(d => d.Shop)
    .Select(g => new
    {
      Shop = g.Key,
      Cartoon = g.Select(i => i.Cartoon).Distinct().Count(),
      Box = g
        .GroupBy(i => i.Cartoon)
        .Select(gr => gr.Select(i => i.Box).Distinct().Count())
        .ToArray()
    }).SelectMany(i => i.Box.Select(ii => new { i.Shop, i.Cartoon, Box = ii }))
    .ToList();