重新想象 Windows 8 Store Apps (22) - 文件系统: 访问文件夹和文件, 通过 AQS 搜索本地文件

<Page
x:Class="XamlDemo.FileSystem.FileAccess"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:XamlDemo.FileSystem"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"> <Grid Background="Transparent">
<StackPanel Margin="120 0 0 0"> <TextBlock Name="lblMsg" FontSize="14.667" /> <ListBox Name="listBox" Width="400" Height="200" SelectionChanged="listBox_SelectionChanged_1" HorizontalAlignment="Left" Margin="0 10 0 0" /> </StackPanel>
</Grid>
</Page>

/*
* 演示如何访问文件夹和文件，以及如何获取文件的各种属性
*
* StorageFolder - 文件夹操作类
* 获取文件夹相关属性、重命名、Create...、Get...等
*
* StorageFile - 文件操作类
* 获取文件相关属性、重命名、Create...、Get...、Copy...、Move...、Delete...、Open...、Replace...等
*
* 注：WinRT 中的关于存储操作的相关类都在 Windows.Storage 命名空间内
*/using System;
using System.Collections.Generic;
using Windows.Storage;
using Windows.Storage.FileProperties;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using System.Linq;namespace XamlDemo.FileSystem
{
public sealed partial class FileAccess : Page
{
public FileAccess()
{
this.InitializeComponent();
} protected async override void OnNavigatedTo(NavigationEventArgs e)
{
// 遍历“文档库”目录下的所有顶级文件（需要在 Package.appxmanifest 中选中“文档库”功能）
StorageFolder storageFolder = KnownFolders.DocumentsLibrary;
IReadOnlyList<StorageFile> files = await storageFolder.GetFilesAsync();
listBox.ItemsSource = files.Select(p => p.Name).ToList();
} private async void listBox_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
// 获取用户选中的文件
string fileName = (string)listBox.SelectedItem;
StorageFolder storageFolder = KnownFolders.DocumentsLibrary;
StorageFile storageFile = await storageFolder.GetFileAsync(fileName); // 显示文件的各种属性
if (storageFile != null)
{
lblMsg.Text = "Name：" + storageFile.Name;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "FileType：" + storageFile.FileType;
lblMsg.Text += Environment.NewLine; BasicProperties basicProperties = await storageFile.GetBasicPropertiesAsync();
lblMsg.Text += "Size：" + basicProperties.Size;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "DateModified：" + basicProperties.DateModified;
lblMsg.Text += Environment.NewLine; /*
* 获取文件的其它各种属性
* 详细属性列表请参见：http://msdn.microsoft.com/en-us/library/windows/desktop/ff521735(v=vs.85).aspx
*/
List<string> propertiesName = new List<string>();
propertiesName.Add("System.DateAccessed");
propertiesName.Add("System.DateCreated");
propertiesName.Add("System.FileOwner");
IDictionary<string, object> extraProperties = await storageFile.Properties.RetrievePropertiesAsync(propertiesName); lblMsg.Text += "System.DateAccessed：" + extraProperties["System.DateAccessed"];
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "System.DateCreated：" + extraProperties["System.DateCreated"];
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "System.FileOwner：" + extraProperties["System.FileOwner"];
}
}
}
}

<Page
x:Class="XamlDemo.FileSystem.FolderAccess"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:XamlDemo.FileSystem"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"> <Grid Background="Transparent">
<StackPanel Margin="120 0 0 0"> <TextBlock Name="lblMsg" FontSize="14.667" /> <Button Name="btnGroupFile" Content="分组文件" Click="btnGroupFile_Click_1" Margin="0 10 0 0" /> <Button Name="btnPrefetchAPI" Content="从 Prefetch 中加载信息" Click="btnPrefetchAPI_Click_1" Margin="0 10 0 0" /> </StackPanel>
</Grid>
</Page>

/*
* 演示遍历文件夹时的一些特殊操作
* 1、演示如何对 StorageFolder 中的内容做分组
* 2、演示如何通过文件扩展名过滤内容，以及如何从 Prefetch 中获取数据
*
* StorageFolder - 文件夹操作类
* 获取文件夹相关属性、重命名、Create...、Get...等
*
* StorageFile - 文件操作类
* 获取文件相关属性、重命名、Create...、Get...、Copy...、Move...、Delete...、Open...、Replace...等
*
* 注：WinRT 中的关于存储操作的相关类都在 Windows.Storage 命名空间内
*/using System;
using System.Collections.Generic;
using Windows.Storage;
using Windows.Storage.FileProperties;
using Windows.Storage.Search;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;namespace XamlDemo.FileSystem
{
public sealed partial class FolderAccess : Page
{
public FolderAccess()
{
this.InitializeComponent();
} // 演示如何对 StorageFolder 中的内容做分组
private async void btnGroupFile_Click_1(object sender, Windows.UI.Xaml.RoutedEventArgs e)
{
lblMsg.Text = ""; StorageFolder picturesFolder = KnownFolders.PicturesLibrary; // 创建一个按月份分组的查询
QueryOptions queryOptions = new QueryOptions(CommonFolderQuery.GroupByMonth);
// 对指定文件夹执行指定的文件夹查询，返回分组后的文件夹数据
StorageFolderQueryResult queryResult = picturesFolder.CreateFolderQueryWithOptions(queryOptions); IReadOnlyList<StorageFolder> folderList = await queryResult.GetFoldersAsync();
foreach (StorageFolder folder in folderList) // 这里的 floder 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 folder.GetFilesAsync();
lblMsg.Text += folder.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;
}
}
} // 演示如何通过文件扩展名过滤内容，以及如何从 Prefetch 中获取数据
private async void btnPrefetchAPI_Click_1(object sender, Windows.UI.Xaml.RoutedEventArgs e)
{
/*
* Prefetch 是预读的文件信息，其在 C:\Windows\Prefetch 目录内，可以从中获取文件属性信息和文件缩略图，在访问大量文件的场景下可以提高效率
*/ lblMsg.Text = ""; List<string> fileTypeFilter = new List<string>();
fileTypeFilter.Add(".jpg");
fileTypeFilter.Add(".png"); // 新建一个查询，指定需要查询的文件的扩展名
QueryOptions queryOptions = new QueryOptions(CommonFileQuery.OrderByName, fileTypeFilter); // 通过 QueryOptions.SetPropertyPrefetch() 来设置需要从 Prefetch 中获取的属性信息
List<string> propertyNames = new List<string>();
propertyNames.Add("System.FileOwner");
queryOptions.SetPropertyPrefetch(PropertyPrefetchOptions.ImageProperties, propertyNames); /*
* 通过 QueryOptions.SetThumbnailPrefetch() 来设置需要从 Prefetch 中获取的缩略图
uint requestedSize = 190;
ThumbnailMode thumbnailMode = ThumbnailMode.PicturesView;
ThumbnailOptions thumbnailOptions = ThumbnailOptions.UseCurrentScale;
queryOptions.SetThumbnailPrefetch(thumbnailMode, requestedSize, thumbnailOptions);
*/ // 对指定文件夹执行指定的文件查询，返回查询后的文件数据
StorageFileQueryResult queryResult = KnownFolders.PicturesLibrary.CreateFileQueryWithOptions(queryOptions); IReadOnlyList<StorageFile> fileList = await queryResult.GetFilesAsync();
foreach (StorageFile file in fileList)
{
lblMsg.Text += file.Name; // 文件名 // 获取图像属性
ImageProperties properties = await file.Properties.GetImagePropertiesAsync();
lblMsg.Text += "(" + properties.Width + "x" + properties.Height + ")"; // 获取其他属性（详细属性列表请参见：http://msdn.microsoft.com/en-us/library/windows/desktop/ff521735(v=vs.85).aspx）
IDictionary<string, object> extraProperties = await file.Properties.RetrievePropertiesAsync(propertyNames);
lblMsg.Text += "(" + extraProperties["System.FileOwner"] + ")"; // 获取缩略图
// StorageItemThumbnail thumbnail = await file.GetThumbnailAsync(thumbnailMode, requestedSize, thumbnailOptions);
}
}
}
}

<Page
x:Class="XamlDemo.FileSystem.ThumbnailAccess"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:XamlDemo.FileSystem"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"> <Grid Background="Transparent">
<ScrollViewer Margin="120 0 0 0">
<StackPanel> <Button Name="btnGetThumbnail" Content="获取文件的缩略图" Click="btnGetThumbnail_Click_1" /> <Image Name="img" Stretch="None" HorizontalAlignment="Left" Margin="0 10 0 0" />
<TextBlock Name="lblMsg" FontSize="14.667" Margin="0 10 0 0" /> </StackPanel>
</ScrollViewer>
</Grid>
</Page>

/*
* 演示如何获取文件的缩略图
*
* 获取指定文件或文件夹的缩略图，返回 StorageItemThumbnail 类型的数据
* StorageFile.GetThumbnailAsync(ThumbnailMode mode, uint requestedSize, ThumbnailOptions options)
* StorageFolder.GetThumbnailAsync(ThumbnailMode mode, uint requestedSize, ThumbnailOptions options)
* ThumbnailMode mode - 用于描述缩略图的目的，以使系统确定缩略图图像的调整方式（PicturesView, VideosView, MusicView, DocumentsView, ListView, SingleItem）
* 关于 ThumbnailMode 的详细介绍参见：http://msdn.microsoft.com/en-us/library/windows/apps/hh465350.aspx
* uint requestedSize - 期望尺寸的最长边长的大小
* ThumbnailOptions options - 检索和调整缩略图的行为（None, ReturnOnlyIfCached, ResizeThumbnail, UseCurrentScale）
*/using System;
using Windows.Storage;
using Windows.Storage.FileProperties;
using Windows.Storage.Pickers;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;namespace XamlDemo.FileSystem
{
public sealed partial class ThumbnailAccess : Page
{
public ThumbnailAccess()
{
this.InitializeComponent();
} private async void btnGetThumbnail_Click_1(object sender, RoutedEventArgs e)
{
if (XamlDemo.Common.Helper.EnsureUnsnapped())
{
FileOpenPicker openPicker = new FileOpenPicker();
openPicker.FileTypeFilter.Add("*"); StorageFile file = await openPicker.PickSingleFileAsync();
if (file != null)
{
ThumbnailMode thumbnailMode = ThumbnailMode.PicturesView;
ThumbnailOptions thumbnailOptions = ThumbnailOptions.UseCurrentScale;
uint requestedSize = ; using (StorageItemThumbnail thumbnail = await file.GetThumbnailAsync(thumbnailMode, requestedSize, thumbnailOptions))
{
if (thumbnail != null)
{
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.SetSource(thumbnail);
img.Source = bitmapImage; lblMsg.Text = "file name: " + file.Name;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "requested size: " + requestedSize;
lblMsg.Text += Environment.NewLine;
lblMsg.Text += "returned size: " + thumbnail.OriginalWidth + "*" + thumbnail.OriginalHeight;
}
}
}
}
}
}
}

/*
* 演示如何通过 AQS - Advanced Query Syntax 搜索本地文件
*/using System;
using System.Collections.Generic;
using Windows.Storage;
using Windows.Storage.BulkAccess;
using Windows.Storage.FileProperties;
using Windows.Storage.Search;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;namespace XamlDemo.FileSystem
{
public sealed partial class AQS : Page
{
public AQS()
{
this.InitializeComponent();
} protected async override void OnNavigatedTo(NavigationEventArgs e)
{
// 准备在“音乐库”中进行搜索（需要在 Package.appxmanifest 的“功能”中选中“音乐库”）
StorageFolder musicFolder = KnownFolders.MusicLibrary; // 准备搜索所有类型的文件
List<string> fileTypeFilter = new List<string>();
fileTypeFilter.Add("*"); // 搜索的查询参数
QueryOptions queryOptions = new QueryOptions(CommonFileQuery.OrderByDate, fileTypeFilter);
// 指定 AQS 字符串，参见 http://msdn.microsoft.com/zh-cn/library/windows/apps/aa965711.aspx
queryOptions.UserSearchFilter = "五月天"; // 根据指定的参数创建一个查询
StorageFileQueryResult fileQuery = musicFolder.CreateFileQueryWithOptions(queryOptions); lblMsg.Text = "在音乐库中搜索“五月天”，结果如下：";
lblMsg.Text += Environment.NewLine; // 开始搜索，并返回检索到的文件列表
IReadOnlyList<StorageFile> files = await fileQuery.GetFilesAsync(); if (files.Count == )
{
lblMsg.Text += "什么都没搜到";
}
else
{
foreach (StorageFile file in files)
{
lblMsg.Text += file.Name;
lblMsg.Text += Environment.NewLine;
}
} // 关于 QueryOptions 的一些用法，更详细的 QueryOptions 的说明请参见 msdn
queryOptions = new QueryOptions();
queryOptions.FolderDepth = FolderDepth.Deep;
queryOptions.IndexerOption = IndexerOption.UseIndexerWhenAvailable;
queryOptions.SortOrder.Clear();
var sortEntry = new SortEntry();
sortEntry.PropertyName = "System.FileName";
sortEntry.AscendingOrder = true;
queryOptions.SortOrder.Add(sortEntry); fileQuery = KnownFolders.PicturesLibrary.CreateFileQueryWithOptions(queryOptions);
}
}
}