c# - 选择每个产品的最后一个不可为空的项目？

Question

假设我有，

class Product
{
    public int Id {get; set;}
    public string Name {get; set;}
    public int Order {get; set;}
}

我的数据有，

products[0] = new Product { Id = 1, Name = "P1", Order = 1 }; 
products[1] = new Product { Id = 1, Name = "P2", Order = 2 }; 
products[2] = new Product { Id = 1, Name = null, Order = 3 }; 
products[3] = new Product { Id = 2, Name = "P3", Order = 4 }; 
products[4] = new Product { Id = 2, Name = null, Order = 5 }; 
products[5] = new Product { Id = 2, Name = null, Order = 6 }; 

我需要的是每个 Product.Id 名称的最后一个(按订单描述排序)不可为空的值。所以我的最终输出看起来像，

items[0] =  new { Id = 1, Name = "P2"}; 
items[1] =  new { Id = 2, Name = "P3"}; 

如果 Id=1，我有 3 个名称(P1、P2、null)和非可为空的名称(P1、P2)，但最后一个是 P3。

Answer 1

这应该按顺序获取最后的产品。

var lastOrders = products
        .Where(x => x.Name != null) // Remove inapplicable data
        .OrderBy(x => x.Order) // Order by the Order
        .GroupBy(x => x.Id) // Group the sorted Products
        .Select(x => x.Last()); // Get the last products in the groups