Linq 中的多個聚合級別

Question

盡管我在主題中提到了“多個聚合級別”，但我不確定我的問題應該被稱為什么。

我想聚合所呈現數據的不同維度。 在此示例中，我試圖通過SalesCode獲取聚合數據，並通過AccountId獲取詳細信息聚合。 所以基本上，我可以獲得與銷售聚合級別關聯的帳戶。

因此我應該得到的輸出應該是這樣的：

我的要求是將數據映射到以下類：

public class Earning
{
    public string EntityId
    {
        get;
        set;
    }

    public string EntityName
    {
        get;
        set;
    }

    public string EntityType
    {
        get;
        set;
    }

    public int TradeCount
    {
        get;
        set;
    }

    public int OrderCount
    {
        get;
        set;
    }

    public decimal PrincipalAmount
    {
        get;
        set;
    }

    public decimal GrossBrokerage
    {
        get;
        set;
    }

    public decimal NetBrokerage
    {
        get;
        set;
    }

    public List<Earning> Detail
    {
        get;
        set;
    }
}

從以下數據來看：

List<Trade> Trades = new List<Trade>(){ 
            new Trade{
                AccountId = "ACT01", 
                SalesCode = "STEVES", 
                PrincipalAmount = 100, 
                GrossBrokerage = 0.64M,
                NetBrokerage = 0.64M
            }, 
            new Trade{
                AccountId = "ACT02", 
                SalesCode = "STEVES", 
                PrincipalAmount = 100, 
                GrossBrokerage = 0.64M,
                NetBrokerage = 0.64M
            }, 
            new Trade{
                AccountId = "ACT01", 
                SalesCode = "STEVES", 
                PrincipalAmount = 50, 
                GrossBrokerage = 0.32M,
                NetBrokerage = 0.32M
            }, 
            new Trade{
                AccountId = "ACT03", 
                SalesCode = "GRAHAMS", 
                PrincipalAmount = 100, 
                GrossBrokerage = 0.64M,
                NetBrokerage = 0.64M
            }, 
        };

到目前為止，我已經在下面提到的工作中嘗試了以下方法，但是我對通過 AccountId 獲得 2nd Level 聚合一無所知。

DotNetFiddle： https ://dotnetfiddle.net/SxGdDD

貿易類看起來像這樣：

public class Trade
{
    public string AccountId
    {
        get;
        set;
    }

    public string SalesCode
    {
        get;
        set;
    }

    public decimal PrincipalAmount
    {
        get;
        set;
    }

    public decimal GrossBrokerage
    {
        get;
        set;
    }

    public decimal NetBrokerage
    {
        get;
        set;
    }
}

Answer 1

你需要另一個GroupBy 。

    var results = (
        from r in Trades
        group r by r.SalesCode
        into g
        select new Earning()
        {
            EntityId = g.Key.ToString(),
            EntityName = g.Key.ToString(),
            TradeCount = g.Count(),
            OrderCount = g.Count(),
            PrincipalAmount = g.Sum(c => c.PrincipalAmount),
            GrossBrokerage = g.Sum(c => c.GrossBrokerage),
            NetBrokerage = g.Sum(c => c.NetBrokerage),
            Detail = g.GroupBy(c=>c.AccountId).Select(c => new Earning()
       // Added GroupBy ---^^
            {
                EntityId = c.Key,
                EntityName = c.Key,
                TradeCount = c.Count(),
                OrderCount = c.Count(),
                PrincipalAmount = c.Sum(p=>p.PrincipalAmount),
                GrossBrokerage =  c.Sum(p=>p.GrossBrokerage),
                NetBrokerage = c.Sum(p=>p.NetBrokerage),

            }).ToList(),
        }).ToList();

    foreach (var item in results)
    {
        Console.WriteLine(item.EntityId);
        Console.WriteLine(string.Format("Total Principal Amount: {0}", item.PrincipalAmount.ToString()));
        Console.WriteLine(string.Format("Total Gross Brokerage Amount: {0}", item.GrossBrokerage.ToString()));
        Console.WriteLine(string.Format("Total Net Brokerage Amount: {0}", item.NetBrokerage.ToString()));

        foreach (Earning detail in item.Detail)
        {
            Console.WriteLine(string.Format("-- Detail {0}/{1}", detail.EntityId, detail.EntityName));
        }
    }