c# - How to use Automapper to construct object without default constructor

Question

My objects don't have a default constructor, they all require a signature of

new Entity(int recordid);

I added the following line:

Mapper.CreateMap<EntityDTO, Entity>().ConvertUsing(s => new Entity(s.RecordId));

This fixes the problem where Automapper is expecting a default constructor, however the only element that is mapped is the record id.

How do I get it to pick up on it's normal mapping? How to get all the properties of the entities to be mapped without having to manually map the properties?

Answer 1

You could use ConstructUsing instead of ConvertUsing. Here's a demo:

using System;
using AutoMapper;

public class Source
{
    public int RecordId { get; set; }
    public string Foo { get; set; }
    public string Bar { get; set; }
}

public class Target
{
    public Target(int recordid)
    {
        RecordId = recordid;
    }

    public int RecordId { get; set; }
    public string Foo { get; set; }
    public string Bar { get; set; }
}


class Program
{
    static void Main()
    {
        Mapper
            .CreateMap<Source, Target>()
            .ConstructUsing(source => new Target(source.RecordId));

        var src = new Source
        {
            RecordId = 5,
            Foo = "foo",
            Bar = "bar"
        };
        var dest = Mapper.Map<Source, Target>(src);
        Console.WriteLine(dest.RecordId);
        Console.WriteLine(dest.Foo);
        Console.WriteLine(dest.Bar);
    }
}