Derived to Derived type mapping

[philippe-lavoie]

I'm mapping classes from one namespace to another, however it looks like that mapster will mapped a derived class to the baseclass instead of mapping it to a derived class. For example, I have a class named Choice and ComplexChoice in both namespaces, if I pass a ComplexChoice as a property to a class, mapping it should also result in a ComplexChoice, the following code can be used to test this

namespace Contracts.Models.FakeOrder
{
    public class ValidateProductsRequest
    {
        public string Id { get; set; }
        public List<ProductItem> Items { get; set; }
    }

    public class ProductItem
    {
        public string ProductId { get; set; }
        public int Quantity { get; set; }
        public decimal Price { get; set; }
        public List<Choice> Choices { get; set; }
    }

    public class Choice
    {
        public ProductItem Item { get; set; }
        public string Instructions { get; set; }
    }

    public class ComplexChoice : Choice
    {
        public string OtherInstruction { get; set; }
    }
}

namespace Contracts.Models.FakeRestaurant
{

    public class ValidateProductsRequest
    {
        public string Id { get; set; }
        public List<ProductItem> Items { get; set; }
    }

    public class ProductItem
    {
        public string ProductId { get; set; }
        public int Quantity { get; set; }
        public decimal Price { get; set; }
        public List<Choice> Choices { get; set; }
    }

    public class Choice
    {
        public ProductItem Item { get; set; }
        public string Instructions { get; set; }
        public decimal ExtraCost { get; set; }
    }

    public class ComplexChoice : Choice
    {
        public string OtherInstruction { get; set; }
    }

}

 [TestClass]
    public class MapsterTest
    {

        public Contracts.Models.FakeOrder.ValidateProductsRequest GetRequest(string id, int nItems = 2, int nChoices = 1)
        {
            var result = new Contracts.Models.FakeOrder.ValidateProductsRequest();
            result.Id = id;
            result.Items = new List<Contracts.Models.FakeOrder.ProductItem>();
            for (int i = 0; i < nItems; i++)
            {
                var item = new Contracts.Models.FakeOrder.ProductItem();
                item.Price = i + 0.99m;
                item.ProductId = id + '-' + i.ToString();
                item.Quantity = i;
                item.Choices = new List<Contracts.Models.FakeOrder.Choice>();
                for (int j = 0; j < nChoices; j++)
                {
                    var choice = new Contracts.Models.FakeOrder.Choice();
                    choice.Item = new Contracts.Models.FakeOrder.ProductItem();
                    choice.Item.ProductId = "Sub" + item.ProductId;
                    choice.Item.Price = 0.15m;
                    choice.Instructions = "Whatever " + id;
                    item.Choices.Add(choice);
                }
                result.Items.Add(item);
            }
            return result;
        }

        [TestMethod]
        public void ValidateMapsterWithChildren()
        {
            TypeAdapterConfig<Contracts.Models.FakeOrder.Choice, Contracts.Models.FakeRestaurant.Choice>.NewConfig();
            TypeAdapterConfig<Contracts.Models.FakeOrder.ComplexChoice, Contracts.Models.FakeRestaurant.ComplexChoice>.NewConfig();
            TypeAdapterConfig<Contracts.Models.FakeOrder.ValidateProductsRequest, Contracts.Models.FakeRestaurant.ValidateProductsRequest>.NewConfig();

            var request = GetRequest("Something");
            var complexChoice = new Contracts.Models.FakeOrder.ComplexChoice();
            complexChoice.OtherInstruction = "Complex stuff";
            request.Items[0].Choices[0] = complexChoice;
            var mappedRequest = TypeAdapter.Adapt<Contracts.Models.FakeRestaurant.ValidateProductsRequest>(request);
            Assert.AreEqual(request.Id, mappedRequest.Id);
            Assert.AreEqual(request.Items.Count, mappedRequest.Items.Count);
            Assert.IsInstanceOfType(mappedRequest.Items[0].Choices[0], typeof(Contracts.Models.FakeRestaurant.ComplexChoice));
            Assert.AreEqual(request.Items[1].Choices[0].Item.ProductId, mappedRequest.Items[1].Choices[0].Item.ProductId);
        }
  }
}

If you could help, it would be greatly appreciated.

[philippe-lavoie]

Doing the following would work, however I still think that there should be a way to configure how derived types should be mapped. Let me know if this is just 'out of scope'. Thanks

 public Contracts.Models.FakeRestaurant.Choice ChoiceChooser(Contracts.Models.FakeOrder.Choice from)
        {
            if(from == null)
            {
                return null;
            }

            switch(from.GetType().Name)
            {
                case "Choice":
                    return new Contracts.Models.FakeRestaurant.Choice();
                case "ComplexChoice":
                    return new Contracts.Models.FakeRestaurant.ComplexChoice();
                default:
                    throw new ArgumentException(nameof(from) + " is not of a valid type");
            }
        }

        [TestMethod]
        public void ValidateMapsterWithChildren()
        {
            TypeAdapterConfig<Contracts.Models.FakeOrder.Choice, Contracts.Models.FakeRestaurant.Choice>.NewConfig()
                .ConstructUsing(src => ChoiceChooser(src));
...

[chaowlert]

Hi, this is interesting feature, however we already capture in #52 and it still open, sorry for this. It is nice that you can find workaround. This will be my to do list (or any PR is welcome).

Thank you,

[philippe-lavoie]

In my case, I'm doing code generation to bridge two code bases, so I just have to do some trickery to auto-add ConstructUsing. However, if I wasn't, manually generating 100 methods to manage custom construction would be problematic (yeah... it's a large code base)

I can perhaps look into a PR, might be easier to do then the code generation :)

[philippe-lavoie]

Turns out that with the current code base, it really looks like everything is tied to a generic which will auto-downgrade to the actual instead of the dynamic derived type. In the case of something simple like

TestRequest
TestRequestChild: TestRequest
TestRequestGrandChild: TestRequestChild

I will have to auto-generate the following methods

using Mapster;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Testing.ExpectedResults
{
    public class RegisterEcpTesting2EcpInternalTesting
    {
        public InternalTesting.TestRequest RegisterFromTestRequest(Testing.TestRequest from)
        {
            if(from == null)
            {
                return null;
            }

            switch(from.GetType().Name)
            {
                case "TestRequest":
                    return new InternalTesting.TestRequest();
                case "TestRequestChild":
                    return new InternalTesting.TestRequestChild();
                case "TestRequestGrandChild":
                    return new InternalTesting.TestRequestGrandChild();
                default:
                    return new InternalTesting.TestRequest();
            }
        }

        public Testing.TestRequest RegisterToTestRequest(InternalTesting.TestRequest from)
        {
            if (from == null)
            {
                return null;
            }

            switch (from.GetType().Name)
            {
                case "TestRequest":
                    return new Testing.TestRequest();
                case "TestRequestChild":
                    return new Testing.TestRequestChild();
                case "TestRequestGrandChild":
                    return new Testing.TestRequestGrandChild();
                default:
                    return new Testing.TestRequest();
            }
        }

        public InternalTesting.TestRequestChild RegisterFromTestRequestChild(Testing.TestRequestChild from)
        {
            if (from == null)
            {
                return null;
            }

            switch (from.GetType().Name)
            {
                case "TestRequestChild":
                    return new InternalTesting.TestRequestChild();
                case "TestRequestGrandChild":
                    return new InternalTesting.TestRequestGrandChild();
                default:
                    return new InternalTesting.TestRequestChild();
            }
        }

        public Testing.TestRequestChild RegisterToTestRequestChild(InternalTesting.TestRequestChild from)
        {
            if (from == null)
            {
                return null;
            }

            switch (from.GetType().Name)
            {
                case "TestRequestChild":
                    return new Testing.TestRequestChild();
                case "TestRequestGrandChild":
                    return new Testing.TestRequestGrandChild();
                default:
                    return new Testing.TestRequestChild();
            }
        }

        public void Register()
        {
            TypeAdapterConfig<Testing.TestRequest, InternalTesting.TestRequest>.NewConfig()
                .ConstructUsing(src => RegisterFromTestRequest(src));
            TypeAdapterConfig<InternalTesting.TestRequest, Testing.TestRequest>.NewConfig()
                .ConstructUsing(src => RegisterToTestRequest(src));
            TypeAdapterConfig<Testing.TestRequestChild, InternalTesting.TestRequestChild>.NewConfig()
                .ConstructUsing(src => RegisterFromTestRequestChild(src));
            TypeAdapterConfig<InternalTesting.TestRequestChild, Testing.TestRequestChild>.NewConfig()
                .ConstructUsing(src => RegisterToTestRequestChild(src));
        }
    }
}

[chaowlert]

Hi, I added Include command in Mapster 3.0 (https://github.com/chaowlert/Mapster/wiki/Config-inheritance), please try. Thx u.