Automapper: How to leverage a custom INamingConvention? - automapper

Question

I am working with a database where the designers really seemed to enjoy capital letters and the underscore key. Since I have a simple ORM, my data models use these names as well. I need to build DTOs and I would prefer to give them standard names since we are exposing them through services.
The code below is now corrected! The test passes so use this as a reference if you need to use multiple naming conventions
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using AutoMapper;
using NUnit.Framework;
namespace AutomapperTest
{
public class DATAMODEL
{
public Guid ID { get; set; }
public string FIRST_NAME { get; set; }
public List<CHILD_DATAMODEL> CHILDREN { get; set; }
}
public class CHILD_DATAMODEL
{
public Guid ID { get; set; }
public int ORDER_ID { get; set; }
}
public class DataModelDto
{
public Guid Id { get; set; }
public string FirstName { get; set; }
public List<ChildDataModelDto> Children { get; set; }
}
public class ChildDataModelDto
{
public Guid Id { get; set; }
public int OrderId { get; set; }
}
public class UpperUnderscoreNamingConvention : INamingConvention
{
private readonly Regex _splittingExpression = new Regex(#"[\p{Lu}0-9]+(?=_?)");
public Regex SplittingExpression { get { return _splittingExpression; } }
public string SeparatorCharacter { get { return "_"; } }
}
public class Profile1 : Profile
{
protected override void Configure()
{
SourceMemberNamingConvention = new UpperUnderscoreNamingConvention();
DestinationMemberNamingConvention = new PascalCaseNamingConvention();
CreateMap<DATAMODEL, DataModelDto>();
CreateMap<CHILD_DATAMODEL, ChildDataModelDto>();
}
}
[TestFixture]
public class Tests
{
[Test]
public void CanMap()
{
//tell automapper to use my convention
Mapper.Initialize(x => x.AddProfile<Profile1>());
//make a dummy source object
var src = new DATAMODEL();
src.ID = Guid.NewGuid();
src.FIRST_NAME = "foobar";
src.CHILDREN = new List<CHILD_DATAMODEL>
{
new CHILD_DATAMODEL()
{
ID = Guid.NewGuid(),
ORDER_ID = 999
}
};
//map to destination
var dest = Mapper.Map<DATAMODEL, DataModelDto>(src);
Assert.AreEqual(src.ID, dest.Id);
Assert.AreEqual(src.FIRST_NAME, dest.FirstName);
Assert.AreEqual(src.CHILDREN.Count, dest.Children.Count);
Assert.AreEqual(src.CHILDREN[0].ID, dest.Children[0].Id);
Assert.AreEqual(src.CHILDREN[0].ORDER_ID, dest.Children[0].OrderId);
}
}
}

Answer 1

Create your mappings in profiles, and define the INamingConvention parameters as appropriate.
I don't like the global/static, so I prefer using Initialize and define all of my mappings together. This also has the added benefit of allowing a call to AssertConfiguration... which means if I've borked my mapping I'll get the exception at launch instead of whenever my code gets around to using the problematic mapping.
Mapper.Initialize(configuration =>
{
configuration.CreateProfile("Profile1", CreateProfile1);
configuration.CreateProfile("Profile2", CreateProfile2);
});
Mapper.AssertConfigurationIsValid();
in the same class with that initialization method:
public void CreateProfile1(IProfileExpression profile)
{
// this.CreateMap (not Mapper.CreateMap) statements that do the "normal" thing here
// equivalent to Mapper.CreateMap( ... ).WithProfile("Profile1");
}
public void CreateProfile2(IProfileExpression profile)
{
profile.SourceMemberNamingConvention = new PascalCaseNamingConvention();
profile.DestinationMemberNamingConvention = new LowerUnderscoreNamingConvention();
// this.CreateMap (not Mapper.CreateMap) statements that need your special conventions here
// equivalent to Mapper.CreateMap( ... ).WithProfile("Profile2");
}
if you do it this way, and don't define the same mapping in both profiles, I don't think you need anything to "fill in the blank" from the original question, it should already be setup to do the right thing.

Answer 2

What about
public class DATAMODELProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<DATAMODEL, DATAMODEL>();
Mapper.CreateMap<DATAMODEL, SOMETHINGELSE>();
Mapper.CreateMap<DATAMODEL, DataModelDto>()
.ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.ID))
.ForMember(dest => dest.FirstName, opt => opt.MapFrom(src => src.FIRST_NAME))
.ForMember(dest => dest.ChildDataModels, opt => opt.MapFrom(src => src.CHILD_DATAMODELS));
}
}