我有一個3層架構(gòu)Web Api解決方案,里面有3個項目：數(shù)據(jù),業(yè)務(wù)和表示層.我需要在兩個業(yè)務(wù)和表示層中初始化兩個不同的映射器.

我已經(jīng)創(chuàng)建了一個靜態(tài)類和方法來初始化業(yè)務(wù)邏輯中的一個映射器：

using AutoMapper;
using Shop.BLL.DTOModels;
using Shop.DAL.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Shop.BLL.InitMapper
{
    public static class InitializeMapperBLL
    {
        public static void RegisterMappings()
        {
            Mapper.Initialize(cfg => cfg.CreateMap<Category, DTOCategoryModel>());
        }
    }
}

并稱之為：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Shop.DAL.Repositories;
using AutoMapper;
using Shop.BLL.DTOModels;
using Shop.DAL.Models;
using Shop.BLL.Interfaces;
using Shop.DAL.Interfaces;
using Shop.BLL.InitMapper;

namespace Shop.BLL.Services
{
    public class CategoryService : ICategoryService
    {
        IUnitOfWork Database { get; set; }

        public CategoryService(IUnitOfWork uow)
        {
            Database = uow;
        }

        public IEnumerable<DTOCategoryModel> GetCategories()
        {
//I call it here
            InitializeMapperBLL.RegisterMappings();

            return Mapper.Map<IEnumerable<Category>, List<DTOCategoryModel>>(Database.Categories.GetAll());
        }
        public void Dispose()
        {
            Database.Dispose();
        }


    }
}

在表示層我做同樣的事情：

using AutoMapper;
using Shop.API.ViewModels;
using Shop.BLL.DTOModels;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Shop.API.MapperInit
{
    public static class InitializeMapperAPI
    {
        public static void RegisterMappings()
        {
            Mapper.Initialize(cfg => cfg.CreateMap<DTOCategoryModel, CategoryViewModel>());
        }
    }
}

并調(diào)用Global.asax

protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            GlobalConfiguration.Configure(WebApiConfig.Register);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
      //here I call it
            InitializeMapperAPI.RegisterMappings();

            CreateKernel();
        }

我已經(jīng)初始化了錯誤Mapper.您必須為每個應(yīng)用程序域/進程調(diào)用一次Initialize.

如何解決這個問題呢？

解決方法:

您可以使用反射和自動播放器配置文件的一種方法.這在我用過的項目中非常有效.

在每個項目/圖層中創(chuàng)建一個automapper配置文件類.每個配置文件類應(yīng)僅包含它自己需要的映射.以下是其中一個的示例：

  //Profile here is of type AutoMapper.Profile
  public class BusinessLayerMapperConfig : Profile
  {
    public BusinessLayerMapperConfig()
    {
      //create layer specific maps
      CreateMap<MyObjectDTO, MyObjectViewModel>();
    }

    public override string ProfileName
    {
      get { return this.GetType().ToString(); }
    }
  }

然后真正靠近應(yīng)用程序入口點的地方(我從Global.asax.cs中的ApplicationStart方法調(diào)用以下方法),初始化所有的配置文件,如下所示：

public static void RegisterMaps()
    {
      //get all projects' AutoMapper profiles using reflection
      var assembliesToScan = System.AppDomain.CurrentDomain.GetAssemblies();
      var allTypes = assembliesToScan.SelectMany(a => a.ExportedTypes).ToArray();

      var profiles =
          allTypes
              .Where(t => typeof(Profile).GetTypeInfo().IsAssignableFrom(t.GetTypeInfo()))
              .Where(t => !t.GetTypeInfo().IsAbstract);

      //add each profile to our static AutoMapper
      Mapper.Initialize(cfg =>
      {
        foreach (var profile in profiles)
        {
          cfg.AddProfile(profile);
        }
      });
    }

這將允許您按照它們使用的圖層邏輯分隔您的地圖,并確保您只初始化它們一次.