//在执行子类构造函数之前，先执行基类Repository<Book>的构造函数
public BookRepository(BookStoreDbContext dbcontext)
: base(dbcontext)
{
}
public Repository(BookStoreDbContext dbContext)
{
this.dbContext = dbContext;
this.dbSet = dbContext.Set <TEntity>();
}
public UnitOfWork(BookStoreDbContext context)
{
_context = context;
}
