如何使用 LINQ 合并来自多个 IEnumerable<T> 的结果

Question

我可以拥有多个（最多 5 个）IEnumerable<ResortSupplier>，并希望通过供应商代码将它们合并为单个 IEnumerable<ResortSupplier> 分组。我的对象如下所示：

这是我的对象：

[Serializable]
public class ResortSupplier
{
    public string SupplierCode { get; set; }
    public IList<Product> ResortProducts { get; set; }
}

[Serializable]
public class Product
{
    public string Code { get; set; }
    //Other fields... 
    public IList<PerPricing> PricingDetail { get; set; }
}

[Serializable]
public class PerPricing
{
    //Other fields..
    public decimal? Price { get; set; }
    public Error PricingError { get; set; }
}

多个 IEnumerable 中的数据可能如下所示：

----------------------------------------
IEnumerable<ResortSupplier> - 1

Hyatt Resort
  Standard Room
    PricingDetail-1
  Superior Room         
    PricingDetail-1

Sandals Resort
  Standard Room
    PricingDetail-1
  Delux Room            
    PricingDetail-1

----------------------------------------
IEnumerable<ResortSupplier> - 2

Hyatt Resort
  Standard Room
    PricingDetail-2
  Superior Room         
    PricingDetail-2
  One Bed Room Suit
    PricingDetail-2

Sandals Resort
  Standard Room
    PricingDetail-2
  Honeymoon Suit            
    PricingDetail-2
----------------------------------------
IEnumerable<ResortSupplier> - 3
.....
----------------------------------------
IEnumerable<ResortSupplier> - 4
.....
----------------------------------------
IEnumerable<ResortSupplier> - 5
.....
----------------------------------------

我的合并结果应包含：

IEnumerable<ResortSupplier> - Consolidated

Hyatt Resort
  Standard Room
    PricingDetail-1
    PricingDetail-2
  Superior Room         
    PricingDetail-1
    PricingDetail-2
  Bed Room Suit
    PricingDetail-2

Sandals Resort
  Standard Room
    PricingDetail-1
    PricingDetail-2
  Delux Room            
    PricingDetail-1
  Honeymoon Suit            
    PricingDetail-2

----------------------------------------

处理此问题的最佳方法是什么？我尝试了简单的 IEnumerable.Union 和 GroupBy 子句，但没有得到我想要的结果。

Answer 1

如果我理解你，你应该使用 Concat 将它们放入一个大集合中，然后你可以随意分组

IEnumerable<ResortSupplier> master = 
    result1.Concat(result2).Concat(result3); //etc

然后像往常一样分组：

var resultGrouped = master.GroupBy(rs => rs.SupplierCode);

Answer 2

我想你想要这样的东西：

// You can construct this with an array if it isn't already in this form.
IEnumerable<IEnumerable<ResortSupplier>> supplierLists = ...

var query = from suppliers in supplierLists
            from supplier in suppliers
            group supplier by supplier.SupplierCode into g

            let products = g.SelectMany(s => s.ResortProducts)
                            .GroupBy(p => p.Code)
                            .Select(prodGroup => new Product
                                    {
                                       Code = prodGroup.Key,
                                       PricingDetail = prodGroup
                                                       .SelectMany(p => p.PricingDetail)
                                                       .ToList()
                                    })

            select new ResortSupplier
            {
                SupplierCode  = g.Key, 
                ResortProducts = products.ToList()                              
            };

不过，这是一个看起来非常可怕的查询。我强烈建议将查询的不同组件分解为单独的（命名良好的）方法。