//原来是通过返回null，如传入了一个空串，来表示获取根目录（根目录实际上不是一个目录）
//现在改进为查不到抛异常，是不是根目录外部判断处理，不通过返回null隐式的表达其它含义
/// <summary>
/// 获取一个文件夹实体
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public WindowFolderEntity GetFolderEntity(string id)
{
if (String.IsNullOrEmpty(id))
{
Debug.Assert(false, "GetFolderEntity 传入的 id 为空");
return(null);
}
XElement element = _indexXml.XPathSelectElement(String.Format(XPATH_Index_SelectFolder, id));
if (element == null)
{
Debug.Assert(false, "GetFolderEntity 失败，返回了 null");
}
WindowFolderEntity formFolderEntity = new WindowFolderEntity();
formFolderEntity.FromXml(element.ToString());
return(formFolderEntity);
}
/// <summary>
/// 获取隶属于指定目录的子目录集合
/// </summary>
/// <param name="folderId"></param>
/// <returns></returns>
public WindowFolderEntityCollection GetFolderCollection(string folderId)
{
if (folderId == null)
{
folderId = String.Empty;
}
WindowFolderEntityCollection collection = new WindowFolderEntityCollection();
foreach (XElement element in
_indexXml.XPathSelectElements(String.Format(XPATH_Index_SelectFolder_ByParentId, folderId)))
{
WindowFolderEntity formFolderEntity = new WindowFolderEntity();
//FormFolderEntity在往Index文件里存的时候是直接ToXml的
//所以此处直接FromXml即可
formFolderEntity.FromXml(element.ToString());
collection.Add(formFolderEntity);
}
return(collection);
}
