Generic Repository EF 5 - Update Entity And It's Complex/Scalar/Navigation Properties - entity-framework

Question

I'm trying to find an easy solution for updating an entity + the included properties in my solution. I've created an Generic Repository for my DBContext (database). It does update the parent entity, but not handling changes on the child properties. Is there a way to handle or track those changes?
Example code for updating child propery: (look at comment - example code)
[HttpPut]
public HttpResponseMessage PutBrand(Brand brand)
{
if (!ModelState.IsValid)
{
return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
}
try
{
// example code
brand.BrandSizes.FirstOrDefault().Name = "I'm a Test";
// add values
brand.State = State.Changed;
brand.DateChanged = DateTime.Now;
// update
brand = _brandService.UpdateBrand(brand);
// save
_brandService.SaveBrandChanges();
// signalR
Hub.Clients.All.UpdateBrand(brand);
return Request.CreateResponse<Brand>(HttpStatusCode.OK, brand);
}
catch (Exception ex)
{
return Request.CreateResponse(HttpStatusCode.InternalServerError, ex.Message);
}
}
Context:
public class ERPContext : DbContext
{
#region Catalog
public DbSet<Brand> Brands { get; set; }
public DbSet<BrandSize> BrandSizes { get; set; }
public DbSet<BrandSizeOption> BrandSizeOptions { get; set; }
public DbSet<BrandTierPrice> BrandTierPrices { get; set; }
#endregion Catalog
public ERPContext()
: base("db-erp")
{
Configuration.LazyLoadingEnabled = false;
Configuration.ProxyCreationEnabled = false;
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
}
Generic Repository:
public class ERPRepository<T> : IRepository<T> where T : class
{
#region Fields
private DbSet<T> _dbSet;
private DbContext _dataContext;
#endregion Fields
#region Ctor
public ERPRepository(DbContext dataContext)
{
if (dataContext == null)
{
throw new ArgumentNullException("dataContext", "dataContext cannot be null");
}
_dataContext = dataContext;
_dbSet = _dataContext.Set<T>();
}
#endregion Ctor
#region Methods
public T Add(T item)
{
return _dbSet.Add(item);
}
public T Delete(T item)
{
return _dbSet.Remove(item);
}
public T Update(T item)
{
var updated = _dbSet.Attach(item);
_dataContext.Entry(item).State = EntityState.Modified;
return updated;
}
public IQueryable<T> Query(params Expression<Func<T, object>>[] includes)
{
var query = _dbSet;
if (includes != null)
{
includes.ToList().ForEach(x => query.Include(x).Load());
}
return query;
}
public void SaveChanges()
{
_dataContext.SaveChanges();
}
#endregion Methods
}
Model:
public class Brand
{
#region Ctr
public Brand()
{
BrandSizes = new List<BrandSize>();
BrandTierPrices = new List<BrandTierPrice>();
}
#endregion Ctr
#region Properties
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int? LogoId { get; set; }
public int DisplayOrder { get; set; }
public bool Deleted { get; set; }
public bool Locked { get; set; }
public State State { get; set; }
public DateTime DateChanged { get; set; }
public DateTime DateCreated { get; set; }
#endregion Properties
#region Mapping
public virtual Picture Logo { get; set; }
public virtual List<BrandSize> BrandSizes { get; set; }
public virtual List<BrandTierPrice> BrandTierPrices { get; set; }
#endregion Mapping
}
BrandService:
public partial class BrandService : IBrandService
{
#region Fields
private readonly IRepository<Brand> _brandRepository;
private readonly IRepository<BrandSize> _brandSizeRepository;
private readonly IRepository<BrandSizeOption> _brandSizeOptionRepository;
#endregion Fields
#region Ctor
public BrandService(IRepository<Brand> brandRepository, IRepository<BrandSize> brandSizeRepository, IRepository<BrandSizeOption> brandSizeOptionRepository)
{
_brandRepository = brandRepository;
_brandSizeRepository = brandSizeRepository;
_brandSizeOptionRepository = brandSizeOptionRepository;
}
#endregion Ctor
#region Methods
public virtual IEnumerable<Brand> GetAllBrands()
{
return _brandRepository.Query(x => x.BrandSizes);
//return _brandRepository.Query();
}
public virtual Brand GetBrandById(int id)
{
return _brandRepository.Query().Where(x => x.Id == id).FirstOrDefault();
}
public virtual Brand InsertBrand(Brand brand)
{
return _brandRepository.Add(brand);
}
public virtual Brand UpdateBrand(Brand brand)
{
return _brandRepository.Update(brand);
}
public virtual Brand DeleteBrand(Brand brand)
{
return _brandRepository.Delete(brand);
}
public virtual void SaveBrandChanges()
{
_brandRepository.SaveChanges();
}
#endregion Methods
}

Answer 1

Create IObjectWithState interface and State enum to track changes manually:
public interface IObjectWithState
{
State State { get; set; }
}
public enum State
{
Added,
Unchanged,
Modified,
Deleted
}
and implement the interface in every mapped entity
public class Brand:IObjectWithState
{ ....
[NotMapped]
public State State { get; set; }}
and add these two helper methods to convert the state and to apply the changes in the entire graph:
public static EntityState ConvertState(State state)
{
switch (state)
{
case State.Added :
return EntityState.Added;
case State.Deleted:
return EntityState.Deleted;
case State.Modified:
return EntityState.Modified;
case State.Unchanged:
return EntityState.Unchanged;
default:
return EntityState.Unchanged;
}
}
public static void ApplyStateChanges(this DbContext context)
{
foreach (var entry in context.ChangeTracker.Entries<IObjectWithState>())
{
IObjectWithState stateInfo = entry.Entity;
entry.State = StateHelpers.ConvertState(stateInfo.State);
}
}
and when update or insert any object edit the state of it like this object.State = State.Modified;
and then modify your insert or update method to be like this:
public void InsertOrUpdate(T entity, bool IsGraph)
{
if (((IObjectWithState)entity).State == State.Added)
{
dataContext.Entry(entity).State = System.Data.Entity.EntityState.Added;
}
else
{
dbset.Add(entity);
dataContext.Entry(entity).State = System.Data.Entity.EntityState.Modified;
}
//This method change the state of every changed object
if (IsGraph)
ApplyStateChanges(dataContext);
dataContext.Commit();
}