c# - Linq 分组求和问题

Question

我有以下实体:

具有订阅列表的帐户类:

public class Account
{
    /// <summary>
    /// Account ID
    /// </summary>
    public string ID { get; set; }

    /// <summary>
    /// A List with all subscriptions
    /// </summary>
    public IEnumerable<Subscription> Subscriptions { get; set; }
}

带有变体和附加组件列表的订阅类:

public class Subscription
{
    /// <summary>
    /// Subscription ID
    /// </summary>
    public string ID { get; set; }

    /// <summary>
    /// Quantity of the subscription.
    /// </summary>
    public int Quantity { get; set; }

    /// <summary>
    /// A list with all subscription add ons
    /// </summary>
    public IEnumerable<AddOn> AddOns { get; set; }

    /// <summary>
    /// A List with all subscription variations
    /// </summary>
    public IEnumerable<Variation> Variations { get; set; }
}

带有变体列表的附加类:

public class AddOn
{
    /// <summary>
    /// Gets or Sets add on id
    /// </summary>
    public string ID { get; set; }

    /// <summary>
    /// Quantity of the add on.
    /// </summary>
    public int Quantity { get; set; }

    /// <summary>
    /// A List with all add on variations
    /// </summary>
    public IEnumerable<Variation> Variations { get; set; }

}

和变体类:

public class Variation
{
    /// <summary>
    /// Variation ID
    /// </summary>
    public string ID { get; set; }

    /// <summary>
    /// offerUri
    /// </summary>
    public string Code { get; set; }

    /// <summary>
    /// Variation Value
    /// </summary>
    public string Value { get; set; }

    /// <summary>
    /// Variation Name
    /// </summary>
    public string Name { get; set; }

}

我想做的是用特定代码对所有附加组件进行分组并对数量求和。例如我试过:

var groupAddOnsByCode = acc.Subscriptions.Select(s => s.AddOns.GroupBy(a => a.Variations.Select(v => v.Code).FirstOrDefault())).ToList();

这是一个正确的附加组件组，但我想要一个列表，其中包含按代码和每个代码的总数量列出的每个订阅组的附加组件。

例如，如果一个订阅有 X 个附加组件，并且每个附加组件的代码是 1、2、...、X，我想按代码和此代码的总数量对附加组件进行分组。如果我有以下结构，我希望结果会是这样的:

具有当前结构的伪代码(代码指的是每个附加组件具有的变体类):

Subscription {
 //a list with X number of add ons
 AddOn1 = { Variation = { Code = 1 }, Quantity = 2 },
 AddOn2 = { Variation = { Code = 2 }, Quantity = 3 },
 ...
 AddOnX = { Variation = { Code = X }, Quantity = 4 }
}

我的期望:

Subscription {
    AddOn1 { Variation = { Code = 1 }, Quantity = totalAmountOfQuantityForAddOnsWithCode = 1 },
    ...
    AddOnX { Variation = { Code = X }, Quantity = totalAmountOfQuantityForAddOnsWithCode = X },
}

您可以使用这个 dotnetfiddle测试虚拟数据。

很抱歉发了这么长的帖子，如果有任何帮助，我将不胜感激。另请记住，我的 C# 和 Linq 知识有限。

Answer 1

如果我理解正确，以下可能会产生预期的结果

var result = acc.Subscriptions.Select(s => new
{
    Subscription = s,
    AddOns = s.AddOns.SelectMany(a => a.Variations, (a, v) => new { a, v })
        .GroupBy(e => e.v.Code, (key, elements) => new 
        { 
            Code = key,
            Quantity = elements.Sum(e => e.a.Quantity)
        }).ToList()
}).ToList();