如何在Windows Phone 8.1中从文件夹相对ID中获取文件夹？
StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(path);
此代码使用完整路径，而不是relativeID。
public sealed class StorageFolder
{
IAsyncOperation<StorageFolder> GetFolderAsync(string name);
。.
StorageFolder folder = await StorageFolder.GetFolderAsync(folderId);