AutoMapper.Mapper.CreateMap<TSource,TDestination>()' is obsolete

Question

I have to classes Like

class A
{
 public int id {get; set;}
}

class B
{
 public C c {get; set;}
}

class C
{
 public int id {get; set;}
 public string Name {get; set;}
}

My requirement is to map id of class A to id of class C. Now what I was doing till now was: Mapper.CreateMap().ForMember(des => des.C.Id, src => src.MapFrom(x => x.id));

and it was working fine.

Now seems like Auto mapper has changed their implementation. and I am getting warning as below:

AutoMapper.Mapper.CreateMap()' is obsolete: 'Dynamically creating maps will be removed in version 5.0. Use a MapperConfiguration instance and store statically as needed, or Mapper.Initialize. Use CreateMapper to create a mapper instance.

I need to map some properties of classes which has different name and structure. Any help on this.

Answer 1

Previously

  Mapper.CreateMap<Src, Dest>()
 .ForMember(d => d.UserName, opt => opt.MapFrom(/* ????? */));

The problem here is mapping definitions are static, defined once and reused throughout the lifetime of the application. Before 3.3, you would need to re-define the mapping on every request, with the hard-coded value. And since the mapping configuration is created in a separate location than our mapping execution, we need some way to introduce a runtime parameter in our configuration, then supply it during execution.

This is accomplished in two parts: the mapping definition where we create a runtime parameter, then at execution time when we supply it. To create the mapping definition with a runtime parameter, we “fake” a closure that includes a named local variable:

Mapper.Initialize(cfg => {

string userName = null;
cfg.CreateMap<Source, Dest>()
    .ForMember(d => d.UserName, 
        opt => opt.MapFrom(src => userName)
    );
});

For more information see this

For one or more classes

 cfg.CreateMissingTypeMaps = true;
 cfg.CreateMap<Source, Dest>()
    .ForMember(d => d.UserName, 
        opt => opt.MapFrom(src => userName)
    );

 cfg.CreateMap<AbcEditViewModel, Abc>();
 cfg.CreateMap<Abc, AbcEditViewModel>();
});

In mapping class

  IMapper mapper = config.CreateMapper();
  var source = new AbcEditViewModel();
  var dest = mapper.Map<AbcEditViewModel, Abct>(source);

Answer 2

Another way that seems a bit cleaner is to make a MappingProfile class which inherits from the Profile class of AutoMapper

public class MappingProfile:Profile
{
    public MappingProfile()
    {
        CreateMap<Source1, Destination1>();
        CreateMap<Source2, Destination2>();
        ...
    }
}

Then you initialize the mapping with Mapper.Initialize(c => c.AddProfile<MappingProfile>()); in your startup code

That will allow you to use the mapping anywhere by calling

destination1Collection = source1Collection.Select(Mapper.Map<Source1, Destination1>);