如何在C#中获取分组/透视数据表中的值

using System;
using System.Collections.Generic;
using System.Linq;

public class Sale
{
    public string Product { get; set; }
    public int Quantity { get; set; }
    public decimal Price { get; set; }
}

public class Program
{
    public static void Main()
    {
        List<Sale> sales = new List<Sale>
        {
            new Sale { Product = "Apple", Quantity = 10, Price = 1.2m },
            new Sale { Product = "Banana", Quantity = 5, Price = 0.8m },
            new Sale { Product = "Apple", Quantity = 7, Price = 1.2m },
            new Sale { Product = "Banana", Quantity = 3, Price = 0.8m },
            new Sale { Product = "Orange", Quantity = 8, Price = 1.5m }
        };

        // 使用 LINQ 进行分组和聚合
        var groupedSales = from sale in sales
                           group sale by sale.Product into productGroup
                           select new
                           {
                               Product = productGroup.Key,
                               TotalQuantity = productGroup.Sum(s => s.Quantity),
                               TotalSales = productGroup.Sum(s => s.Quantity * s.Price)
                           };

        // 打印结果
        foreach (var group in groupedSales)
        {
            Console.WriteLine($"Product: {group.Product}, Total Quantity: {group.TotalQuantity}, Total Sales: {group.TotalSales:C}");
        }
    }
}

Product: Apple, Total Quantity: 17, Total Sales: $20.40
Product: Banana, Total Quantity: 8, Total Sales: $6.40
Product: Orange, Total Quantity: 8, Total Sales: $12.00

var groupedSales = sales
    .GroupBy(sale => sale.Product)
    .Select(productGroup => new
    {
        Product = productGroup.Key,
        TotalQuantity = productGroup.Sum(s => s.Quantity),
        TotalSales = productGroup.Sum(s => s.Quantity * s.Price)
    });

foreach (var group in groupedSales)
{
    Console.WriteLine($"Product: {group.Product}, Total Quantity: {group.TotalQuantity}, Total Sales: {group.TotalSales:C}");
}