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program_me95
·
如何在LINQ中正确分组数据？（C#中的Group by）
大家好！我刚开始学习C#中的LINQ，在使用GroupBy时遇到了问题。我有一个订单列表，想按客户名称分组，以便查看每个客户花费了多少。这是我的代码：
```csharp
public class Order
{
public int OrderId { get; set; }
public string CustomerName { get; set; }
public decimal Amount { get; set; }
public DateTime OrderDate { get; set; }
}
List orders = new List
{
new Order { OrderId = 1, CustomerName = "伊万", Amount = 250, OrderDate = DateTime.Now.AddDays(-1) },
new Order { OrderId = 2, CustomerName = "玛丽亚", Amount = 400, OrderDate = DateTime.Now },
new Order { OrderId = 3, CustomerName = "伊万", Amount = 150, OrderDate = DateTime.Now.AddDays(-2) },
new Order { OrderId = 4, CustomerName = "彼得", Amount = 600, OrderDate = DateTime.Now },
new Order { OrderId = 5, CustomerName = "玛丽亚", Amount = 300, OrderDate = DateTime.Now.AddDays(-3) }
};
