Question

我有以下示例类。

public class Parent
{
    public int Id { get; set; }
    public List<Child> Children { get; set; }
}

public class Child
{
    public string Category { get; set; }
    public decimal? Price { get; set; }
}

以及以下示例数据。

var parents = new List<Parent>()
{
    new Parent() {
        Id = 1,
        Children = new List<Child>
        {
            new Child {Category = "Item 1", Price = 10 },
            new Child {Category = "Item 2", Price = 30 },
            new Child {Category = "Item 3", Price = null },
            new Child {Category = "Item 4", Price = 5 },
            new Child {Category = "Item 5", Price = 20 }
        }
    },
    new Parent() {
        Id = 2,
        Children = new List<Child>
        {
            new Child {Category = "Item 1", Price = null },
            new Child {Category = "Item 2", Price = null },
            new Child {Category = "Item 3", Price = null },
            new Child {Category = "Item 4", Price = null },
            new Child {Category = "Item 5", Price = null }
        }
    },
    new Parent() {
        Id = 3,
        Children = new List<Child>
        {
            new Child {Category = "Item 1", Price = 100 },
            new Child {Category = "Item 2", Price = 300 },
            new Child {Category = "Item 3", Price = null },
            new Child {Category = "Item 4", Price = 50 },
            new Child {Category = "Item 5", Price = 200 }
        }
    },
};

如何使用LINQ按Parent的特定类别定价Child个对象，比如说“第3项”？

Answer 1

试试这个：

var resultSet = parents.OrderBy(o => o.Children.Where(e => e.Category == "Item 3").Max(i => i.Price)).ToList();

Answer 2

您可以执行以下操作：

parents.OrderBy(x => x.Children.Where(y => y.Category == "Item 3").Max(z => z.Price));

OrderBy子集合特定类别

2 个答案: