C# AutoMapper Array to a List

Question

I have read AutoMapping Array to a List but this is actually List to Array and I do want Array to List. Here is my code:

using AutoMapper;
using System;
using System.Collections.Generic;
using System.Linq;

namespace PocArrayListMap
{
    class Destination
    {
        public List<string> list = new List<string>();
    }

    class Origin
    {
        public string[] array;
    }

    class Program
    {
        static void Main(string[] args)
        {
            Mapper.Initialize(cfg => cfg.CreateMap<Origin, Destination>().ForMember(e => e.list, opts => opts.MapFrom(s => s.array.ToList())));

            var config = new MapperConfiguration(cfg => cfg.CreateMap<Origin, Destination>());
            config.AssertConfigurationIsValid(); // Exception here

            var o = new Origin() { array = new string[] { "one", "two", "three" } };

            var d = Mapper.Map<Destination>(o);

            Console.WriteLine(string.Join(", ", d.list));
        }
    }
}

and here is the exception message:

Origin -> Destination (Destination member list)

PocArrayListMap.Origin -> PocArrayListMap.Destination (Destination member list)

Unmapped properties:

list

Using the latest nuget of Automapper (6.2.2) and .Net 4.6.2 Not that it is platform or version related.

edit as said here, https://stackoverflow.com/a/5591125/169714 automapper should do list and array stuff automatically. But I keep getting unmapped properties. Even when I have the ForMember method.

Why don't you configure the member mapping in `new MapperConfiguration` instead of calling `Mapper.Initialize`. Do you expect the initialize to have any effect on your newly created configuration? — grek40, Jan 04 '18 at 09:09

score 2 · Accepted Answer · answered Jan 04 '18 at 09:09

I tried this code (with Automapper 6.2.2) and it's working on my side:

class Program
{
    static void Main(string[] args)
    {
        Mapper.Initialize(cfg => cfg.CreateMap<Origin, Destination>().ForMember(e => e.list, opts => opts.MapFrom(s => s.array.ToList())));
        Mapper.AssertConfigurationIsValid();

        Origin o = new Origin {array = new[] {"one", "two", "three"}};
        Destination d = Mapper.Map<Destination>(o);

        Console.WriteLine(string.Join(", ", d.list));
    }
}

score 0 · Answer 2 · answered Jan 04 '18 at 09:06

Is your list containing any items? Because I can't see if you assign a value to it, from my view your list is empty...

In this thread, one of the comments was: "Now that 5.0.1 had come out I had to change this to CreateMap(MemberList.None) otherwise I would get the error".

Hope I helped!

C# AutoMapper Array to a List

2 Answers2