将 MaxDepth 设置为 1 时，Automapper 10 不会 map 集合属性

Question

Properties of type ICollection are not mapped when migrating from Automapper 9 to 10. I am using .NET 5.

I have the following setup:

private class Class1
{
    public int Id { get; set; }
}

private class Class2
{
     public int Id { get; set; }
     public ICollection<Class1> ChildClasses { get; set; }
}

private class Class2Bis
{
     public int Id { get; set; }
     public ICollection<Class1> ChildClasses { get; set; }
}

private class MapperProfile : Profile
{
     public MapperProfile()
     {
          CreateMap<Class2, Class2Bis>().ReverseMap();
     }
}

I am injecting the mapper using a helper method that uses AutoMapper.Extensions.Microsoft.DependencyInjection module:

public static IServiceCollection AddMapper(this IServiceCollection services, params Assembly[] assemblies)
{
    return services.AddAutoMapper(cfg =>
    {
        cfg.ForAllMaps((map, exp) => exp.MaxDepth(1));
        cfg.AllowNullCollections = true;
        cfg.ShouldMapProperty = p => p.GetMethod.IsPublic || p.GetMethod.IsAssembly;
    },
    assemblies);
}

The following test succeeds using Automapper 9 but fails using Automapper 10:

    [Fact]
    public void Should_Map_ClassesWithCollectionProperties()
    {
        var object2 = new Class2
        {
            Id = 1,
            ChildClasses = new List<Class1>() 
            {
                new Class1 
                {
                    Id = 1
                }
            }
        };

        var object2Bis = _mapper.Map<Class2Bis>(object2);

        Assert.Equal(object2.ChildClasses.Count, object2Bis.ChildClasses.Count);
    }

object2Bis has an empty ChildClasses property when using Automapper 10.

Answer 1

Removing cfg.ForAllMaps((map, exp) => exp.MaxDepth(1)); or setting MaxDepth to 2 (or higher number) makes the code work for me. There is next note in the 10.0 Upgrade Guide :

When reaching MaxDepth , destination collections are null/empty, they used to contain null values.