Generic Repository Complete

GenericRepository2.cs

namespace CodedHomes.Data
{
    public class GenericRepository<T> : IRepository<T> where T : class
    {
        protected DbSet<T> DBSet { get; set; }
        protected DbContext Context { get; set; }

        public GenericRepository(DbContext context)
        {
	  if (context == null)	  
	      throw new ArgumentException("An argument of context its necesary.");

	  this.Context = context;
	  this.DBSet = this.Context.Set<T>();
        }

        public IQueryable<T> GetAll() {
	  return this.DBSet;
        }

        public T GetById(int id){
	  return this.DBSet.Find(id);
        }

        public void Add(T entity) {
	  
	  DbEntityEntry entry = this.Context.Entry(entity);
	  if (entry.State != EntityState.Detached)	
	      entry.State = EntityState.Added;
	  this.DBSet.Add(entity);
        }

        public void Update(T entity)
        {
	  DbEntityEntry entry = this.Context.Entry(entity);
	  if (entry.State == EntityState.Detached)
	      this.DBSet.Attach(entity);
	  entry.State = EntityState.Modified;
        }

        public void Delete(T entity)
        {
	  DbEntityEntry entry = this.Context.Entry(entity);
	  if (entry.State != EntityState.Deleted)
	      entry.State = EntityState.Deleted;
	  else{
	      this.DBSet.Attach(entity);
	      this.DBSet.Remove(entity);
	  }
        }

        public void Delete(int id)
        {
	  var entity = this.GetById(id);

	  if (entity != null)
	      this.Delete(entity);
        }

        public void Detach(T entity)
        {
	  DbEntityEntry entry = this.Context.Entry(entity);

	  entry.State = EntityState.Detached;

        }
        
    }
}