使用Automapper投影

Question

I need made a projection from database to model entity. Before get data in database and map to Entity with unity of word and reposy:

 public async Task<IEnumerable<Entity>> GetProjectsSponsorByYear(Guid idUser)
    {
        logger.Trace("Called GetProjectsSponsorByYear method in ProjectBusiness");
        var Entitys = await this.unitOfWork.Repository<Entity>().Queryable().Where(p => p.SponsorId == idUser && p.Draft == true).ToListAsync();


 return listProjectDataBaseAsModel;

, after that use automapper for create a map between Entity and model:

this.CreateMap<Entity, Model>()
            .ForMember(dest => dest.ID, opt => opt.MapFrom(src => src.ID))
            .ForMember(dest => dest.Title, opt => opt.MapFrom(src => src.Title))


public async Task<IEnumerable<Model>> GetProjectHistoricList()
    {
        logger.Trace("Called GetProjectHistoricList method in ProjectService");

        var allProjects = await this.projectBusiness.GetAll();

        var allProjectsGrid = this.entityMapper.Map<IEnumerable<Entity>, IEnumerable<Model>>(allProjects);

        return allProjectsGrid;
    }

But now i need made a projection from database to model entity, the problem is when use createMap, for configuration automapper, i have property with method

 .ForMember(dest => dest.ImpactSupervisorDescription, opt => opt.MapFrom(src => src.ImpactSupervisor.GetDescription()))

when made the projection between repository and model with ProjectTo method a get Exection from Linq. I know this exection is for Linq create a query and not implement this method into her.

Need to know if there is any way to achieve this, either before or after the projection.

Answer 1

Check out the AutoMapper.EF6 project, it uses another project, DelegateDecompiler, to build out projections based on the method and property contents. It examines the IL and builds an expression to match that IL to then pass to your queryable provider:

https://www.nuget.org/packages/AutoMapper.EF6/

Then you can project straight from the queryable to list:

var allProjectsGrid = await this.projectBusiness.GetAll()
                                .ProjectToListAsync<Model>();

And as a side note, you don't need those ForMember calls for ID and Title, that's the Auto part of AutoMapper :)