EF Code First check for property in generic repository - entity-framework

Question

In my project, I'm using EF Code First approach following Code Camper structure. So i have generic repository IRepository;
public interface IRepository<T> where T : class
{
IQueryable<T> GetAll();
T GetById(int id);
void Add(T entity);
void Update(T entity);
void Delete(T entity);
void Delete(int id);
}
and then it's implementation EFRepository<T>
public class EFRepository<T> : IRepository<T> where T : class
{
public EFRepository(DbContext dbContext)
{
if (dbContext == null)
throw new ArgumentNullException("dbContext");
DbContext = dbContext;
DbSet = DbContext.Set<T>();
}
protected DbContext DbContext { get; set; }
protected DbSet<T> DbSet { get; set; }
public virtual IQueryable<T> GetAll()
{
return DbSet;
}
public virtual T GetById(int id)
{
//return DbSet.FirstOrDefault(PredicateBuilder.GetByIdPredicate<T>(id));
return DbSet.Find(id);
}
public virtual void Add(T entity)
{
DbEntityEntry dbEntityEntry = DbContext.Entry(entity);
if (dbEntityEntry.State != EntityState.Detached)
{
dbEntityEntry.State = EntityState.Added;
}
else
{
DbSet.Add(entity);
}
}
public virtual void Update(T entity)
{
DbEntityEntry dbEntityEntry = DbContext.Entry(entity);
if (dbEntityEntry.State == EntityState.Detached)
{
DbSet.Attach(entity);
}
dbEntityEntry.State = EntityState.Modified;
}
public virtual void Delete(T entity)
{
DbEntityEntry dbEntityEntry = DbContext.Entry(entity);
if (dbEntityEntry.State != EntityState.Deleted)
{
dbEntityEntry.State = EntityState.Deleted;
}
else
{
DbSet.Attach(entity);
DbSet.Remove(entity);
}
}
public virtual void Delete(int id)
{
var entity = GetById(id);
if (entity == null) return; // not found; assume already deleted.
Delete(entity);
}
}
Based on customer needs, i should not delete any DB records, so for most(not all of them) tables I have isDeleted property to mark record as deleted. And these records which marked as isDeleted should not appear to users
My question is: How in my generic repository implementation check for that isDeleted property while I'm expecting generic object T.
For example GetAll function should be:
public virtual IQueryable<T> GetAll()
{
return DbSet.where(x=>x.isDelete == false);
}
Any ideas, how i can do that?

Answer 1

Create an interface with IsDeleted property and inherit all your models from it. Then you could modify your repository like this:
public class EFRepository<T> : IRepository<T> where T : TypeOfYourNewInterface
Now you can access IsDeleted in generic methods.

Answer 2

I could not find a suitable solution to my problem. After more searching i ended with 3 solutions:
Create extension methods.
Create a custom IDbSet which can accept a filter expression.
Add a discriminator to every model.
I choosed solution(3) although, I don't like it much