新增这样做是可以新增 但下面修改就不行
public void Add(Role role, long[] userIds, long[] functionIds)
        {
            if (Exists(role.RoleName)) throw new BusinessRuleValidationException("角色名已存在");

            if (userIds != null && userIds.Length > 0)
                role.Users = _userRepository.GetAll().Where(t => userIds.Contains(t.Id)).ToList();
            if (functionIds != null && functionIds.Length > 0)
                role.Functions = _functionRepository.GetAll().Where(t => functionIds.Contains(t.Id)).ToList();
            _roleRepository.Insert(role);
            this._unitOfWork.Commit();
        }

但是这样修改就不行了
public void Modify(Role role, long[] userIds, long[] functionIds)
        {
            if (Exists(role.RoleName, role.Id)) throw new BusinessRuleValidationException("角色名已存在");
            var roleData = _roleRepository.GetAll().Include(t => t.Users).Include(t => t.Functions).FirstOrDefault(t => t.Id == role.Id);
            roleData.RoleName = role.RoleName.Trim();
            roleData.Description = role.Description;
            roleData.Users.Clear();
            roleData.Functions.Clear();
            if (userIds != null && userIds.Length > 0)
                _userRepository.GetAll().Where(t => userIds.Contains(t.Id)).ToList().ForEach(x => roleData.Users.Add(x));
            if (functionIds != null && functionIds.Length > 0)
               _functionRepository.GetAll().Where(t => functionIds.Contains(t.Id)).ToList().ForEach(x => roleData.Functions.Add(x));
            _roleRepository.Update(roleData);
            this._unitOfWork.Commit();
        }
这个是修改方法
public virtual TEntity Update(TEntity entity)
        {
            _entities.Entry(entity).State = System.Data.Entity.EntityState.Modified;
            return entity;
        }