自动映射器投影不包括深度嵌套的层次对象

Question

I'm trying to use AutoMapper v6.1.1 to map a class using projection, but AutoMapper doesn't include deeply nested objects.

I've attached a complete Visual Studio 2015 solution with a unit test here: https://www.dropbox.com/s/omue5ou5dvxsa57/UnitTestProject2.zip?dl=0

I'm basically trying to map a Child and Parent hierarchy into a Person hierarchy, but the grand- Parents aren't getting included in the projection result.

Models:

public class Child
{
    public string Name { get; set; }

    public virtual Parent Parent { get; set; }
}

public class Parent
{
    public string Name { get; set; }

    public virtual Parent GrandParent { get; set; }
}

public class Person
{
    public string Name { get; set; }

    public virtual Person Parent { get; set; }
}

Mapping profile:

public class PersonProfile : Profile
{
    public PersonProfile()
    {
        this.CreateMap<Child, Person>()
            .MaxDepth(5);
        this.CreateMap<Parent, Person>()
            .ForMember(destinationMember => destinationMember.Parent, memberOptions => memberOptions.MapFrom(sourceMember => sourceMember.GrandParent))
            .MaxDepth(5);
    }
}

Unit test:

[TestClass]
public class UnitTest1
{
    IMapper mapper;
    List<Child> children;

    [TestInitialize]
    public void TestInitialize()
    {
        MapperConfiguration configuration = new MapperConfiguration((config =>
        {
            config.AddProfile(new PersonProfile());
            config.ForAllMaps((mapType, mapperExpression) =>
            {
                mapperExpression.MaxDepth(5);
            });
        }));

        this.mapper = configuration.CreateMapper();

        mapper.ConfigurationProvider.AssertConfigurationIsValid();

        this.children = new List<Child>
        {
            new Child
            {
                Name = "Child1",
                Parent = new Parent
                {
                    Name = "Parent1",
                    GrandParent = new Parent
                    {
                        Name = "GrandParent1",
                        GrandParent = new Parent
                        {
                            Name = "GreatGrandParent1"
                        }
                    }
                }
            }
        };
    }

    [TestMethod]
    public void TestProjection()
    {
        IQueryable<Person> people = children.AsQueryable().ProjectTo<Person>(mapper.ConfigurationProvider);

        AssertPeople(people);
    }

    [TestMethod]
    public void TestMap()
    {
        List<Person> people = mapper.Map<List<Child>, List<Person>>(children);

        AssertPeople(people.AsQueryable());
    }

    private void AssertPeople(IQueryable<Person> people)
    {
        Assert.IsNotNull(people);
        Assert.AreEqual(1, people.Count());

        Person child1 = people.ElementAt(0);
        Assert.AreEqual("Child1", child1.Name);

        Person parent1 = child1.Parent;
        Assert.IsNotNull(parent1);
        Assert.AreEqual("Parent1", parent1.Name);

        Person grandParent1 = parent1.Parent;
        Assert.IsNotNull(grandParent1); // fails when using ProjectTo
        Assert.AreEqual("GrandParent1", grandParent1.Name);
    }
}

Using the Map method works but ProjectTo doesn't.

The classes in the sample code are much simpler than those used in production.

I'm trying to use projection so that I can return an IQueryable<Person> from OData and take advantage of the SQL generated by LINQ to Entities with query options automatically applied.

Any help is appreciated.

Thank you!

Answer 1

I think this describes the issue: https://github.com/AutoMapper/AutoMapper/issues/2171

But as a workaround is it not possible to create an extension method that basically calls the Map internally:

public static class Extenstions
{
    public static IQueryable<TDestination> ProjectToExt<TDestination, TSource>(this IQueryable<TSource> @this,
        IMapper mapper)
    {
        return mapper.Map<IEnumerable<TDestination>>(@this).AsQueryable();
    }
}

Then the calling code is like:

IQueryable<Person> people = children.AsQueryable().ProjectToExt<Person, Child>(mapper);