public void deleteCategory(int id)
{
DanhMucSach e = db.DanhMucSaches.SingleOrDefault(x => x.MaDanhMuc == id);
db.DanhMucSaches.Remove(e);
db.SaveChanges();
}
public void createCategory(DanhMucSach e)
{
db.DanhMucSaches.Add(e);
db.SaveChanges();
}