EntityFramework用法探索（四）Repository和UnitOfWork-阿里云开发者社区

EntityFramework用法探索（四）Repository和UnitOfWork

2017-12-15 1767

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简介：

以上一篇CodeFirst生成代码为基础，继续探索使用方式。

引入Repository模式，定义最简单的IRepository接口，仅包含增删改查接口，

1   public interface IRepository<T>
2     where T : class
3   {
4     IQueryable<T> Query();
5     void Insert(T entity);
6     void Update(T entity);
7     void Delete(T entity);
8   }

引入UnitOfWork模式，因为EntityFramework会负责失败回滚，所以此处只定义提交方法。

1   public interface IUnitOfWork
2   {
3     void Commit();
4   }

实现IRepository接口，

 1   public class Repository<T> : IRepository<T> where T : class
 2   {
 3     private readonly IObjectSetFactory _objectSetFactory;
 4     private readonly IObjectSet<T> _objectSet;
 5 
 6     public Repository(IObjectSetFactory objectSetFactory)
 7     {
 8       _objectSetFactory = objectSetFactory;
 9       _objectSet = objectSetFactory.CreateObjectSet<T>();
10     }
11 
12     #region IRepository<T> Members
13 
14     public IQueryable<T> Query()
15     {
16       return _objectSet;
17     }
18 
19     public void Insert(T entity)
20     {
21       _objectSet.AddObject(entity);
22     }
23 
24     public void Update(T entity)
25     {
26       _objectSet.Attach(entity);
27       _objectSetFactory.ChangeObjectState(entity, EntityState.Modified);
28     }
29 
30     public void Delete(T entity)
31     {
32       _objectSet.DeleteObject(entity);
33     }
34 
35     #endregion
36   }

实现IUnitOfWork接口，

 1   public class UnitOfWork : IUnitOfWork, IDisposable
 2   {
 3     private readonly IObjectContext _objectContext;
 4 
 5     public UnitOfWork(IObjectContext objectContext)
 6     {
 7       _objectContext = objectContext;
 8     }
 9 
10     #region IUnitOfWork Members
11 
12     public void Commit()
13     {
14       _objectContext.SaveChanges();
15     }
16 
17     #endregion
18 
19     #region IDisposable Members
20 
21     public void Dispose()
22     {
23       if (_objectContext != null)
24       {
25         _objectContext.Dispose();
26       }
27 
28       GC.SuppressFinalize(this);
29     }
30 
31     #endregion
32   }

CustomerRepository类的实现需要做一些配置，

 1     public CustomerRepository()
 2     {
 3       Mapper.CreateMap<DomainModels.Customer, Customer>();
 4       Mapper.CreateMap<Customer, DomainModels.Customer>();
 5 
 6       DbContext context = new RETAILContext();
 7       DbContextAdapter contextAdaptor = new DbContextAdapter(context);
 8 
 9       IObjectSetFactory objectSetFactory = contextAdaptor;
10       _repository = new Repository<Customer>(objectSetFactory);
11 
12       IObjectContext objectContext = contextAdaptor;
13       _uow = new UnitOfWork(objectContext);
14     }

则具体增删改查的逻辑实现，

 1     public void InsertCustomer(DomainModels.Customer customer)
 2     {
 3       Customer entity = Mapper.Map<DomainModels.Customer, Customer>(customer);
 4 
 5       _repository.Insert(entity);
 6       _uow.Commit();
 7 
 8       customer.Id = entity.Id;
 9     }
10 
11     public void UpdateCustomer(DomainModels.Customer customer)
12     {
13       Customer entity = _repository.Query().Single(c => c.Id == customer.Id);
14 
15       entity.Name = customer.Name;
16       entity.Address = customer.Address;
17       entity.Phone = customer.Phone;
18 
19       _repository.Update(entity);
20 
21       _uow.Commit();
22     }

在同样的示例下仍然可以工作，

 1       ICustomerRepository customerRepository = new CustomerRepository();
 2 
 3       // =============== 增 ===============
 4       Console.ForegroundColor = ConsoleColor.DarkRed;
 5 
 6       DomainModels.Customer customer1 = new DomainModels.Customer()
 7       {
 8         Name = "Dennis Gao",
 9         Address = "Beijing",
10         Phone = "18888888888",
11       };
12       customerRepository.InsertCustomer(customer1);
13       Console.WriteLine(customer1);