/// <summary>
/// 变更推荐内容的排列顺序
/// </summary>
/// <param name="id">待调整的推荐Id</param>
/// <param name="referenceId">参照推荐Id</param>
public void ChangeDisplayOrder(long id, long referenceId)
{
//设计要点
//1、交换id和referenceId对应推荐内容的DisplayOrder
RecommendItem item = recommendItemRepository.Get(id);
RecommendItem referenceItem = recommendItemRepository.Get(referenceId);
long itemId = item.DisplayOrder;
item.DisplayOrder = referenceItem.DisplayOrder;
recommendItemRepository.Update(item);
referenceItem.DisplayOrder = itemId;
recommendItemRepository.Update(referenceItem);
}
