AutoMapper用于嵌套项目集合

Question

我有以下模型：

public class Order
{
    public long OrderId { get; set; }

    public ICollection<Order_OrderItem> Order_OrderItems { get; set; }
}

public class Order_OrderItem
{
    public long OrderId { get; set; }

    public virtual Order Order { get; set; }

    public int OrderItemId { get; set; }

    public virtual OrderItem OrderItem { get; set; }
}

我在下面创建了DTO：

public class OrderDto
{
    public long OrderId { get; set; }

    public IEnumerable<OrderItemDto> OrderItems { get; set; }
}

如何将Order映射到OrderDto？

我在下面遇到错误：

configuration.CreateMap<Order, OrderDto>()
    .ForMember(desc => desc.OrderItems,
        opt => opt.MapFrom(src => src.Order_OrderItems));

我检查了其他相关问题，建议与map属性相关，但我的OrderItems是一个集合属性。我怎么能映射它？

任何帮助都将不胜感激。

更新

更改以下配置：

configuration.CreateMap<Order_OrderItem, OrderItemDto>();
configuration.CreateMap<Order, OrderDto>()
    .ForMember(desc => desc.OrderItems,
        opt => opt.MapFrom(src => src.Order_OrderItems));

检查结果时，OrderItems中的OrderDto将为null：

var result = ObjectMapper.Map<OrderDto>(order);

Answer 1

从OrderItem映射到OrderItemDto：

configuration.CreateMap<OrderItem, OrderItemDto>();

从Order映射到OrderDto：

configuration.CreateMap<Order, OrderDto>()
    .ForMember(dest => dest.OrderItems,
        opt => opt.MapFrom(src => src.Order_OrderItems.Select(o => o.OrderItem)));