使用实体框架代码创建存储库第一个4.3

Question

不久前,我使用linq to sql创建了存储库和服务,我很难理解它.我终于明白了,但现在我正在尝试使用Code First EF做同样的事情.我首先对代码的工作方式感到困惑.如果我有一个存储库,我只能传入一个类对象并有select(),ect ......这是如何交互的,或者我如何将它连接到/ DbContext？如果有人可以指出我正确的方向或给我一些建议,将不胜感激.谷歌上的这个东西并不多,因为它仍然是一个相对较新的模式.

如何使用/我会使用DbSet吗？这些存储库很酷但令人困惑.

   public class IRepository<T> : IDisposable
        where T : class, new()
{
    IQueryable<T> Select();

    IQueryable<T> SelectWith(params Expression<Func<T, object>>[] includeProperties);

    T GetById(int id);

    T GetByIdWith(int id, params Expression<Func<T, object>>[] includeProperties);

    void InsertOnCommit(T model);

    void DeleteOnCommit(T model);

}


public class DataContext : DbContext
{
}

Answer 1

这是ASP.Net的 EF中的Repository和UnitOfWork 教程.希望这有帮助.(UnitOfWork是为了确保多个存储库共享相同的DataContext)

通用存储库:

   public class GenericRepository<TEntity> where TEntity : class 
    { 
        internal SchoolDBContext context; 
        internal DbSet<TEntity> dbSet; 

        public GenericRepository(SchoolDBContext context) 
        { 
            this.context = context; 
            this.dbSet = context.Set<TEntity>(); 
        } 

        public virtual IEnumerable<TEntity> Get( 
          Expression<Func<TEntity, bool>> filter = null, 
          Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, 
          string includeProperties = "") 
        {
        ...
        }

        public virtual TEntity GetByID(object id) 
        { 
           return dbSet.Find(id); 
        }

        public virtual void Insert(TEntity entity) 
        { 
          dbSet.Add(entity); 
        } 

      ...
     }

UnitOfWork:调用Save()方法更新存储库中的所有更改.

public class UnitOfWork : IDisposable 
{ 
    private SchoolDBContext context = new SchoolDBContext(); 
    private GenericRepository<Department> departmentRepository; 

    public GenericRepository<Department> DepartmentRepository 
    { 
        get 
        { 

            if (this.departmentRepository == null) 
            { 
                this.departmentRepository = new GenericRepository<Department>(context); 
            } 
            return departmentRepository; 
        } 
    }

    public void Save() 
    { 
        context.SaveChanges(); 
    }
    ....
 }

控制器:

 public class CourseController : Controller 
 { 
     private UnitOfWork unitOfWork = new UnitOfWork(); 

     // 
     // GET: /Course/ 

     public ViewResult Index() 
     { 
         var courses = unitOfWork.CourseRepository.Get(includeProperties: "Department"); 
         return View(courses.ToList()); 
    }

    ....
}