Repository pattern by using entity framework

Question

Following is my code. I want to know it is true or not.

public interface IRepository<T> : IDisposable
{
    IQueryable<T> GetAll();
    T Update(T entity);
    T Insert(T entity);
    T GetById(T entity);
    void Delete(T entity);
    void Save();
}

public class Repository<T> : IRepository<T> where T : class
{
    private readonly SchoolDBEntities _context;

    public Repository(SchoolDBEntities context)
    {
        _context = context;
    }

    public IQueryable<T> GetAll()
    {
        return _context.Set<T>();
    }

    public T Update(T entity)
    {
        var result = _context.Set<T>().Attach(entity);
        _context.Entry(entity).State = EntityState.Modified;
        return result;
    }

    public T Insert(T entity)
    {
        return _context.Set<T>().Add(entity);
    }

    public T GetById(T entity)
    {
        return _context.Set<T>().Find(entity);
    }

    public void Delete(T entity)
    {
        _context.Set<T>().Remove(entity);
    }

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

    public void Dispose()
    {
        _context.Dispose();
    }
}

The problem is, I don't know when and where to call the Save and Dispose methods.

sunil · Accepted Answer · 2013-10-24 15:01:21Z

2

Don't do dispose in IRepository<T>

Try UnitOfWork pattern like this

public interface IUnitOfWork : IDisposable
{
    IRepository<Cart> CartRepository { get; }
    IRepository<Product> ProductRepository { get; }
    void Save();
}

public class UnitOfWork : IUnitOfWork
{
    readonly SqlDbContext _context;
    public UnitOfWork()
    {
        _context = new SqlDbContext();
    }

    private bool _disposed;
    protected virtual void Dispose(bool disposing)
    {
        if (!_disposed)
        {
            if (disposing)
            {
                _context.Dispose();
            }
        }
        _disposed = true;
    }
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

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

    public IGenericRepository<Cart> CartRepository
    {
        get { return new Repository<Cart>(_context); }
    }

    public IGenericRepository<User> UserRepository
    {
        get { return new Repository<User>(_context); }
    }
}

You can call it like this

using (_unitOfWork) 
{ 
   var p = _unitOfWork.ProductRepository.SingleOrDefault(p => p.Id == productId); 
   _cartRepository.Add(p);
   _unitOfWork.Save(); 
}

edited Oct 24, 2013 at 15:01

answered Oct 23, 2013 at 16:46

sunil

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2 Comments

sunil Over a year ago

Often, you will run into scenarios where you need to call methods from 2 or more repositories. So, you will have do using (_cartRepository){} and using (_productRepository){}, here essentially you opening and closing a connection to database twice, which can be avoided using the UnitOfWork pattern like this

using (_unitOfWork)      {         var p = _unitOfWork.ProductRepository.SingleOrDefault(p => p.Id == productId);         _cartRepository.Add(p);        _unitOfWork.Save();      }

maulik13 Over a year ago

Your comment should be part of the answer to add reasoning behind your answer.

korovaisdead · Accepted Answer · 2013-10-23 12:57:20Z

0

I think it depends on the way you use this repo. So save when you want to save and dispose when you want to finish your work ... on application close etc..

answered Oct 23, 2013 at 12:57

korovaisdead

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Comments

Andrei Zubov · Accepted Answer · 2013-10-23 14:46:10Z

0

As you use a Unit of Work pattern here, obviously you should call Save method if user (of a repository) send save changes command. It could be a person clicking Apply changes button on one of your Edit forms or other part of your application which handles some transaction logic and saves/discards changes based on it. So basically, when the logical set of changes is ready to be save, Repository takes care of it.

answered Oct 23, 2013 at 14:46

Andrei Zubov

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