Creating Repository Using Entity Framework Code First 4.3

Question

A while back i created repositories and services using linq to sql and I struggled to understand it. I finally understood it but Now I'm trying to do the same thing but using Code First EF. I'm confused on how this works with code first. If I have one repository that I can just pass in a class object and have select(), ect...How does this interact or how do I connect this to the/a DbContext? If someone can point me in the right direction or give me some advice it would be appreciated. Not much on this stuff on google since it's a relatively new pattern still.

How to use / would I use DbSet? These repositories are cool but confusing.

   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
{
}

You can declare a private field like private DataContext context in the repositories implement IRepository<T>. — Kirin Yao
– Kirin Yao, Commented Mar 13, 2012 at 6:22

Min Min · Accepted Answer · 2012-03-13 03:52:33Z

Here is a Tutorial of Repository and UnitOfWork in EF from ASP.Net. Hope this help. (UnitOfWork is to make sure multiple repositores share the same DataContext)

Generic Repository:

   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: Call the Save() method to update all your changes in repositories.

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(); 
    }
    ....
 }

Controller:

 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()); 
    }

    ....
}

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