// 分组文件夹
private async void btnFolderGroup_Click(object sender, RoutedEventArgs e)
{
lblMsg.Text = "";
StorageFolder picturesFolder = await KnownFolders.GetFolderForUserAsync(null, KnownFolderId.PicturesLibrary);
// 文件夹按月分组查询参数，其他多种分组方式请参见 CommonFolderQuery 枚举
CommonFolderQuery folderQuery = CommonFolderQuery.GroupByMonth;
// 判断一下 picturesFolder 是否支持指定的查询参数
if (picturesFolder.IsCommonFolderQuerySupported(folderQuery))
{
// 创建查询
StorageFolderQueryResult queryResult = picturesFolder.CreateFolderQuery(folderQuery);
// 执行查询
IReadOnlyList <StorageFolder> folderList = await queryResult.GetFoldersAsync();
foreach (StorageFolder storageFolder in folderList) // 这里的 storageFolder 就是按月份分组后的月份文件夹（当然，物理上并没有月份文件夹）
{
IReadOnlyList <StorageFile> fileList = await storageFolder.GetFilesAsync();
lblMsg.Text += storageFolder.Name + " (" + fileList.Count + ")";
lblMsg.Text += Environment.NewLine;
foreach (StorageFile file in fileList) // 月份文件夹内的文件
{
lblMsg.Text += " " + file.Name;
lblMsg.Text += Environment.NewLine;
}
}
}
}
public override bool IsCommonFolderQuerySupported(CommonFolderQuery query) => false;
public override IAsyncOperation <IReadOnlyList <BaseStorageFolder> > GetFoldersAsync(CommonFolderQuery query)
{
return(AsyncInfo.Run <IReadOnlyList <BaseStorageFolder> >(async(cancellationToken) =>
{
return await GetFoldersAsync();
}));
}
public override IAsyncOperation <IReadOnlyList <BaseStorageFolder> > GetFoldersAsync(CommonFolderQuery query, uint startIndex, uint maxItemsToRetrieve)
{
return(AsyncInfo.Run <IReadOnlyList <BaseStorageFolder> >(async(cancellationToken) =>
{
var items = await GetFoldersAsync();
return items.Skip((int)startIndex).Take((int)maxItemsToRetrieve).ToList();
}));
}
public override StorageFolderQueryResult CreateFolderQuery(CommonFolderQuery query) => throw new NotSupportedException();
private async void GetThumbnailButton_Click(object sender, RoutedEventArgs e)
{
rootPage.ResetOutput(ThumbnailImage, OutputTextBlock, OutputDetails);
// Pick a folder
FolderPicker folderPicker = new FolderPicker();
foreach (string extension in FileExtensions.Image)
{
folderPicker.FileTypeFilter.Add(extension);
}
StorageFolder folder = await folderPicker.PickSingleFolderAsync();
if (folder != null)
{
const CommonFolderQuery monthShape = CommonFolderQuery.GroupByMonth;
// Verify queries are supported because they are not supported in all picked locations.
if (folder.IsCommonFolderQuerySupported(monthShape))
{
// Convert folder to file group and query for items
IReadOnlyList <StorageFolder> months = await folder.CreateFolderQuery(monthShape).GetFoldersAsync();
if (months != null && months.Count > 0)
{
const ThumbnailMode thumbnailMode = ThumbnailMode.PicturesView;
const uint size = 200;
StorageFolder firstMonth = months[0];
using (StorageItemThumbnail thumbnail = await firstMonth.GetThumbnailAsync(thumbnailMode, size))
{
if (thumbnail != null)
{
MainPage.DisplayResult(ThumbnailImage, OutputTextBlock, thumbnailMode.ToString(), size, firstMonth, thumbnail, true);
// Also display the hierarchy of the file group to better visualize where the thumbnail comes from
IReadOnlyList <StorageFile> files = await firstMonth.GetFilesAsync();
if (files != null)
{
StringBuilder output = new StringBuilder("\nList of files in this group:\n\n");
foreach (StorageFile file in files)
{
output.AppendFormat("{0}\n", file.Name);
}
OutputDetails.Text = output.ToString();
}
}
else
{
rootPage.NotifyUser(Errors.NoImages, NotifyType.StatusMessage);
}
}
}
else
{
rootPage.NotifyUser(Errors.FileGroupEmpty, NotifyType.StatusMessage);
}
}
else
{
rootPage.NotifyUser(Errors.FileGroupLocation, NotifyType.StatusMessage);
}
}
else
{
rootPage.NotifyUser(Errors.Cancel, NotifyType.StatusMessage);
}
}
IAsyncOperation <IReadOnlyList <StorageFolder> > IStorageFolderQueryOperations.GetFoldersAsync(CommonFolderQuery query)
{
return(AsyncInfo.Run <IReadOnlyList <StorageFolder> >(async(cancellationToken) =>
{
return await Task.WhenAll((await GetFoldersAsync(query)).Select(x => x.ToStorageFolderAsync().AsTask()));
}));
}
IAsyncOperation <IReadOnlyList <StorageFolder> > IStorageFolderQueryOperations.GetFoldersAsync(CommonFolderQuery query, uint startIndex, uint maxItemsToRetrieve)
{
return(AsyncInfo.Run <IReadOnlyList <StorageFolder> >(async(cancellationToken) =>
{
return await Task.WhenAll((await GetFoldersAsync(query, startIndex, maxItemsToRetrieve)).Select(x => x.ToStorageFolderAsync().AsTask()));
}));
}
public abstract bool IsCommonFolderQuerySupported(CommonFolderQuery query);
public abstract IAsyncOperation <IReadOnlyList <BaseStorageFolder> > GetFoldersAsync(CommonFolderQuery query);
public abstract IAsyncOperation <IReadOnlyList <BaseStorageFolder> > GetFoldersAsync(CommonFolderQuery query, uint startIndex, uint maxItemsToRetrieve);
public abstract StorageFolderQueryResult CreateFolderQuery(CommonFolderQuery query);
public override bool IsCommonFolderQuerySupported(CommonFolderQuery query)
{
return(Folder.IsCommonFolderQuerySupported(query));
}
public override IAsyncOperation <IReadOnlyList <BaseStorageFolder> > GetFoldersAsync(CommonFolderQuery query)
{
return(AsyncInfo.Run <IReadOnlyList <BaseStorageFolder> >(async(cancellationToken) =>
{
var items = await Folder.GetFoldersAsync(query);
return items.Select(x => new SystemStorageFolder(x)).ToList();
}));
}
public override StorageFolderQueryResult CreateFolderQuery(CommonFolderQuery query)
{
return(Folder.CreateFolderQuery(query));
}
