1. 首先安装 Automapper 库，使用以下命令：

Install-Package AutoMapper

2. 在应用程序中创建模型类和 DTO（Data Transfer Object）类。例如：

public class Order
{
    public int Id { get; set; }
    public string OrderNumber { get; set; }
    public List OrderItems { get; set; }
}

public class OrderDto
{
    public int Id { get; set; }
    public string OrderNumber { get; set; }
    public List OrderItems { get; set; }
}

public class OrderItem
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class OrderItemDto
{
    public int Id { get; set; }
    public string Name { get; set; }
}

3. 在应用程序中创建 AutoMapper 配置。创建一个映射配置文件（AutomapperProfile.cs），添加以下内容：

using AutoMapper;
using System.Linq;

public class AutomapperProfile : Profile
{
    public AutomapperProfile()
    {
        CreateMap()
            .ForMember(dest => dest.OrderItems, opt => opt.MapFrom(src => src.OrderItems.Select(x => x)));
            
        CreateMap();
    }
}

4. 在应用程序中使用 AutoMapper 进行映射。例如：

var config = new MapperConfiguration(cfg => cfg.AddProfile());
var mapper = new Mapper(config);

var order = new Order
{
    Id = 1,
    OrderNumber = "ORD-123",
    OrderItems = new List
    {
        new OrderItem { Id = 1, Name = "Product 1" },
        new OrderItem { Id = 2, Name = "Product 2" }
    }
};

var orderDto = mapper.Map(order);

Console.WriteLine($"Order: {order.OrderNumber}");
foreach (var item in order.OrderItems)
{
    Console.WriteLine($"Order item: {item.Name}");
}

Console.WriteLine("-----");

Console.WriteLine($"Order: {orderDto.OrderNumber}");
foreach (var item in orderDto