Where to place AutoMapper.CreateMaps?

asp.net-mvc, automapper, configuration, design-patterns

Solution

Doesn't matter, as long as it's a static class. It's all about convention.

Our convention is that each "layer" (web, services, data) has a single file called `AutoMapperXConfiguration.cs`, with a single method called `Configure()`, where `X` is the layer.

The `Configure()` method then calls `private` methods for each area.

Here's an example of our web tier config:

public static class AutoMapperWebConfiguration
{
   public static void Configure()
   {
      ConfigureUserMapping();
      ConfigurePostMapping();
   }

   private static void ConfigureUserMapping()
   {
      Mapper.CreateMap<User,UserViewModel>();
   } 

   // ... etc
}

We create a method for each "aggregate" (User, Post), so things are separated nicely.

Then your `Global.asax`:

AutoMapperWebConfiguration.Configure();
AutoMapperServicesConfiguration.Configure();
AutoMapperDomainConfiguration.Configure();
// etc

It's kind of like an "interface of words" - can't enforce it, but you expect it, so you can code (and refactor) if necessary.

EDIT:

Just thought I'd mention that I now use AutoMapper profiles, so the above example becomes:

public static class AutoMapperWebConfiguration
{
   public static void Configure()
   {
      Mapper.Initialize(cfg =>
      {
        cfg.AddProfile(new UserProfile());
        cfg.AddProfile(new PostProfile());
      });
   }
}

public class UserProfile : Profile
{
    protected override void Configure()
    {
         Mapper.CreateMap<User,UserViewModel>();
    }
}

Much cleaner/more robust.

Problem

I'm using `AutoMapper` in an `ASP.NET MVC` application. I was told that I should move the `AutoMapper.CreateMap` elsewhere as they have a lot of overhead. I'm not too sure how to design my application to put these calls in just 1 place. I have a web layer, service layer and a data layer. Each a project of its own. I use `Ninject` to DI everything. I'll utilize `AutoMapper` in both web and service layers. So what are your setup for `AutoMapper`'s CreateMap? Where do you put it? How do you call it?

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