我们紧接着上篇,这篇将介绍如何使用Windows.Storage.Compression API来实现解压缩
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我们紧接着上篇,这篇将介绍如何使用Windows.Storage.Compression API来实现解压缩。
本篇将介绍如下五个方面:
a)读取未压缩文件的数据
b)使用指定的压缩算法压缩
c)写压缩数据到新文件
d)从压缩文件中读数据
e)解压数据
我们的创建的步骤如下:
1)为了组织文件方便,我们先建一个文件夹CompressionAndDecompression
2)向文件夹中添加如下一个文件:
CompressionAndDecompression.xaml
创建方法请参照前一篇.
3)此时的解决方案结构如下:
4)向我们的DataSource添加导航所需要的信息
修改我们的SampleDataSource.cs文件中的SampleDataSource类中的代码,
代码如下:
View Code
public SampleDataSource() { #region Group1 var group1 = new SampleDataGroup("FilePicker", "Use Windows.Storage.Pickers API", "Access and save files using the file picker", "Assets/FilePicker.jpg", ""); group1.Items.Add(new SampleDataItem("FilePicker-PickASinglePhoto", "Pick a single photo", "only one file can selected,file type is jpg,jpeg,png", "Assets/FilePicker.jpg", "only one file can selected ", "", group1, typeof(PickASinglePhoto))); group1.Items.Add(new SampleDataItem("FilePicker-PickMultipleFiles", "Pick multiple files", "you can pick multiple files", "Assets/FilePicker.jpg", "pick multiple files", "", group1, typeof(PickMultipleFiles))); group1.Items.Add(new SampleDataItem("FilePicker-PickAFolder", "Pick a folder", "you can pick a folder", "Assets/FilePicker.jpg", "Pick a folder", "", group1, typeof(PickAFolder))); group1.Items.Add(new SampleDataItem("FilePicker-SaveAFile", "Save a file", "you can save a file", "Assets/FilePicker.jpg", "Save a file", "", group1, typeof(SaveAFile))); this.AllGroups.Add(group1); #endregion #region Group2 var group2 = new SampleDataGroup("FileAceess", "Using Windows.Storage API", "File access", "Assets/FileAccess.jpg", ""); group2.Items.Add(new SampleDataItem("FileAceess-CreatingAFile", "Create a file", "Using CreateFileAsync Create a file", "Assets/FileAccess.jpg", "Using CreateFileAsync", "", group2, typeof(CreatingAFile))); group2.Items.Add(new SampleDataItem("FileAceess-WritingAndReadingText", "Write And Read A Text", "Using WriteTextAsync，ReadTextAsync Write And Read Text", "Assets/FileAccess.jpg", "Using WriteTextAsync，ReadTextAsync", "", group2, typeof(WritingAndReadingText))); group2.Items.Add(new SampleDataItem("FileAceess-WritingAndReadingBytes", "Writing and reading bytes in a file", "Using WriteBufferAsync，ReadBufferAsync Write And Read bytes", "Assets/FileAccess.jpg", "Using WriteBufferAsync，ReadBufferAsync", "", group2, typeof(WritingAndReadingBytes))); group2.Items.Add(new SampleDataItem("FileAceess-WritingAndReadingUsingStream", "Writing and reading using a stream", "Using OpenAsync Writing and reading using a stream", "Assets/FileAccess.jpg", "Using OpenAsync", "", group2, typeof(WritingAndReadingUsingStream))); group2.Items.Add(new SampleDataItem("FileAceess-DisplayingFileProperties", "Displaying file properties", "Using GetBasicPropertiesAsync Get File Properties", "Assets/FileAccess.jpg", "Using GetBasicPropertiesAsync", "", group2, typeof(DisplayingFileProperties))); group2.Items.Add(new SampleDataItem("FileAceess-PersistingAccess", "Persisting access to a storage item for future use", "Using MostRecentlyUsedList", "Assets/FileAccess.jpg", "Using MostRecentlyUsedList", "", group2, typeof(PersistingAccess))); group2.Items.Add(new SampleDataItem("FileAceess-CopyAFile", "Copy a file", "Using CopyAsync Copy a file", "Assets/FileAccess.jpg", "Using CopyAsync", "", group2, typeof(CopyAFile))); group2.Items.Add(new SampleDataItem("FileAceess-DeleteAFile", "Delete a file", "Using DeleteAsync Delete a file", "Assets/FileAccess.jpg", "Using DeleteAsync", "", group2, typeof(DeleteAFile))); this.AllGroups.Add(group2); #endregion #region Group3 var group3 = new SampleDataGroup("AccountPictureName", "Use Windows.System.UserProfile API", "Account Picture Name", "Assets/AccountPictureName.jpg", ""); group3.Items.Add(new SampleDataItem("AccountPictureName-GetUserDisplayName", "Get User DisplayName", "Use UserInformation.GetDisplayNameAsync Get User DisplayName", "Assets/AccountPictureName.jpg", "Use UserInformation.GetDisplayNameAsync", "", group3, typeof(GetUserDisplayName))); group3.Items.Add(new SampleDataItem("AccountPictureName-GetUserFirstLastName", "Get First Last Name", "Use UserInformation.GetFirstNameAsync,GetLastNameAsync Get First Name", "Assets/AccountPictureName.jpg", "Use UserInformation.GetFirstNameAsync ", "", group3, typeof(GetUserFirstLastName))); group3.Items.Add(new SampleDataItem("AccountPictureName-GetAccountPicture", "Get Account Picture", "Use UserInformation.GetAccountPicture Get Account Picture", "Assets/AccountPictureName.jpg", "Use UserInformation.GetAccountPicture", "", group3, typeof(GetAccountPicture))); group3.Items.Add(new SampleDataItem("AccountPictureName-SetAccountPictureAndListen", "Set AccountPicture And Listen", "Use UserInformation.SetAccountPicturesAsync Set AccountPicture", "Assets/AccountPictureName.jpg", "Use UserInformation.SetAccountPicturesAsync", "", group3, typeof(SetAccountPictureAndListen))); this.AllGroups.Add(group3); #endregion #region Group4 var group4 = new SampleDataGroup("ApplicationSettings", "ApplicationSettings", " Use the Windows.UI.ApplicationSettings namespace and WinJS.UI.SettingsFlyout", "Assets/ApplicationSettings.jpg", ""); group4.Items.Add(new SampleDataItem("ApplicationSettings-Default", "Default behavior with no settings integration", "Default behavior ", "Assets/ApplicationSettings.jpg", "Default behavior with no settings integration", "", group4, typeof(Default))); group4.Items.Add(new SampleDataItem("ApplicationSettings-AddSettings", "Add settings commands to the settings charm", "Add settings", "Assets/ApplicationSettings.jpg", "Add settings commands to the settings charm ", "", group4, typeof(AddSettings))); this.AllGroups.Add(group4); #endregion #region Group5 var Group5 = new SampleDataGroup("AssociationLaunching", "Use Windows.System.Launcher API", "Association Launching", "Assets/AssociationLaunching.jpg", ""); Group5.Items.Add(new SampleDataItem("AssociationLaunching-LaunchFile", "Launching a file", "Use Windows.System.Launcher.LaunchFileAsync", "Assets/AssociationLaunching.jpg", "Use Windows.System.Launcher.LaunchFileAsync", "", Group5, typeof(LaunchFile))); Group5.Items.Add(new SampleDataItem("AssociationLaunching-LaunchUri", "Launching a URI", "Use Windows.System.Launcher.LaunchUriAsync", "Assets/AssociationLaunching.jpg", "Use Windows.System.Launcher.LaunchUriAsync", "", Group5, typeof(LaunchUri))); Group5.Items.Add(new SampleDataItem("AssociationLaunching-ReceiveFile", "Receiving a file", "Receiving a file", "Assets/AssociationLaunching.jpg", "Receiving a file", "", Group5, typeof(ReceiveFile))); Group5.Items.Add(new SampleDataItem("AssociationLaunching-ReceiveUri", "Receiving a URI", "Receiving a URI", "Assets/AssociationLaunching.jpg", "Receiving a URI", "", Group5, typeof(ReceiveUri))); this.AllGroups.Add(Group5); #endregion #region Group6 var Group6 = new SampleDataGroup("BackgroundTransfer", "Use Windows.Networking.BackgroundTransfer API", "BackgroundDownloader And BackgroundUploader", "Assets/BackgroundTransfer.jpg", ""); Group6.Items.Add(new SampleDataItem("BackgroundTransfer-DownloadFile", "Download Files", "Use BackgroundDownloader", "Assets/BackgroundTransfer.jpg", "BackgroundDownloader", "", Group6, typeof(DownloadFile))); Group6.Items.Add(new SampleDataItem("BackgroundTransfer-UploadFile", "Upload Files", "Use BackgroundUploader", "Assets/BackgroundTransfer.jpg", "BackgroundUploader", "", Group6, typeof(UploadFile))); this.AllGroups.Add(Group6); #endregion #region Group7 var Group7 = new SampleDataGroup("Clipboard", "Use Windows.ApplicationModel.DataTransfer API", "ClipboardOperation", "Assets/Clipboard.jpg", ""); Group7.Items.Add(new SampleDataItem("Clipboard-CopyAndPasteText", "Copy and paste text", "Use Clipboard.GetContent，Clipboard.SetContent", "Assets/Clipboard.jpg", "Clipboard.GetContent，Clipboard.SetContent", "", Group7, typeof(CopyAndPasteText))); Group7.Items.Add(new SampleDataItem("Clipboard-CopyAndPasteImage", "Copy and paste an image", "Use Clipboard.GetContent，Clipboard.SetContent", "Assets/Clipboard.jpg", "Clipboard.GetContent，Clipboard.SetContent", "", Group7, typeof(CopyAndPasteImage))); Group7.Items.Add(new SampleDataItem("Clipboard-CopyAndPasteFile", "Copy and paste files", "Use Clipboard.GetContent，Clipboard.SetContent", "Assets/Clipboard.jpg", "Clipboard.GetContent，Clipboard.SetContent", "", Group7, typeof(CopyAndPasteFile))); Group7.Items.Add(new SampleDataItem("Clipboard-OtherClipboardOperation", "Other Clipboard operations", "Use Clipboard.GetContent，Clipboard.SetContent", "Assets/Clipboard.jpg", "Clipboard.GetContent，Clipboard.SetContent", "", Group7, typeof(OtherClipboardOperation))); this.AllGroups.Add(Group7); #endregion #region Group8 var Group8 = new SampleDataGroup("Compression", "Use Windows.Storage.Compression API", "Compression And Decompression", "Assets/Compression.jpg", ""); Group8.Items.Add(new SampleDataItem("Compression-CompressionAndDecompression", "Compression And Decompression", "Use Windows.Storage.Compression API", "Assets/Compression.jpg", "Compression And Decompression", "", Group8, typeof(CompressionAndDecompression))); this.AllGroups.Add(Group8); #endregion }
5)我们的导航这样就做好了,效果图:
点击 Compression
6)压缩和解压文件
我们使用Compressor压缩文件，
使用Decompression解压文件.
首先修改Package.appxmanifest文件:
修改CompressionAndDecompression.xaml的xaml:
View Code
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Grid x:Name="Input" Grid.Row="0"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <TextBlock x:Name="InputTextBlock1" TextWrapping="Wrap" Grid.Row="0" Style="{StaticResource SubheaderTextStyle}" HorizontalAlignment="Left" > Demonstrates how to use the Windows.Storage.Compression namespace in C#. <LineBreak/> <LineBreak/> Compression algorithms: <LineBreak/> DEFAULT: No compression algorithms explicitly specified. Xpress is used by default. <LineBreak/> XPRESS: Compression ratio is fair. Fastest compression and decompression speeds. Lowest memory requirement. <LineBreak/> XPRESSHUFF: Compression ratio is fair. Fast compression and decompression speeds. Low memory requirement. <LineBreak/> MSZIP: Compression ratio is high. Normal compression speed and fast decompression speed. Low memory requirement. <LineBreak/> LZMS: Compression ratio is highest. Medium compression speed and normal decompression speed. High memory requirement. <LineBreak/> </TextBlock> <StackPanel Orientation="Horizontal" Margin="0,10,0,0" Grid.Row="1"> <Button x:Name="Default" Content="DEFAULT (XPRESS)" Margin="0,0,10,0" Click="Default_Click"/> <Button x:Name="Xpress" Content="XPRESS" Margin="0,0,10,0" Click="Xpress_Click"/> <Button x:Name="XpressHuff" Content="XPRESSHUFF" Margin="0,0,10,0" Click="XpressHuff_Click"/> <Button x:Name="Mszip" Content="MSZIP" Margin="0,0,10,0" Click="Mszip_Click"/> <Button x:Name="Lzms" Content="LZMS" Margin="0,0,10,0" Click="Lzms_Click"/> </StackPanel> </Grid> <Grid x:Name="Output" HorizontalAlignment="Left" VerticalAlignment="Top" Grid.Row="1"> <TextBlock x:Name="OutputText" Width="1000" TextWrapping="Wrap" Style="{StaticResource SubheaderTextStyle}"/> </Grid> </Grid>
修改后台代码:
View Code
public sealed partial class CompressionAndDecompression : Page { public CompressionAndDecompression() { this.InitializeComponent(); } /// <summary> /// Invoked when this page is about to be displayed in a Frame. /// </summary> /// <param name="e">Event data that describes how this page was reached. The Parameter /// property is typically used to configure the page.</param> protected override void OnNavigatedTo(NavigationEventArgs e) { } /// <summary> /// This is the main worker. /// </summary> /// <param name="Algorithm"> /// Comression algorithm to use. If no value is provided compressor will be created using /// Compressor(IInputStream) constructor, otherwise extended version will be used: /// Compressor(IInputStream, CompressAlgorithm, uint) /// </param> private async void DoWork(CompressAlgorithm? Algorithm) { try { OutputText.Text = ""; OutputText.Text = "Working..."; var picker = new FileOpenPicker(); picker.FileTypeFilter.Add("*"); //选择一个文件 var originalFile = await picker.PickSingleFileAsync(); if (originalFile == null) { throw new OperationCanceledException("No file has been selected"); } OutputText.Text += String.Format("\"{0}\" has been picked\n", originalFile.Name); var compressedFilename = originalFile.Name + ".compressed"; //在文档库创建文件 //注意此处需要先声明中加文件关联.compressed和.decompressed，否则文档库拒绝访问 var compressedFile = await KnownFolders.DocumentsLibrary.CreateFileAsync(compressedFilename, CreationCollisionOption.GenerateUniqueName); OutputText.Text += String.Format("\"{0}\" has been created to store compressed data\n", compressedFile.Name); //打开一个随机访问流，读取文件内容 using (var originalInput = await originalFile.OpenReadAsync()) //在压缩目标文件打开一个随机访问流 using (var compressedOutput = await compressedFile.OpenAsync(FileAccessMode.ReadWrite)) //创建压缩对象 using (var compressor = !Algorithm.HasValue ? new Compressor(compressedOutput.GetOutputStreamAt(0)) : new Compressor(compressedOutput.GetOutputStreamAt(0), Algorithm.Value, 0)) { OutputText.Text += "All streams wired for compression\n"; //实现压缩 var bytesCompressed = await RandomAccessStream.CopyAsync(originalInput,compressor); //完成压缩 var finished = await compressor.FinishAsync(); OutputText.Text += String.Format("Compressed {0} bytes into {1}\n", bytesCompressed, compressedOutput.Size); } var decompressedFilename = originalFile.Name + ".decompressed"; var decompressedFile = await KnownFolders.DocumentsLibrary.CreateFileAsync(decompressedFilename, CreationCollisionOption.GenerateUniqueName); OutputText.Text += String.Format("\"{0}\" has been created to store decompressed data\n", decompressedFile.Name); //打开一个顺序访问流来读取文件内容 using (var compressedInput = await compressedFile.OpenSequentialReadAsync()) //创建解压对象 using (var decompressor = new Decompressor(compressedInput)) using (var decompressedOutput = await decompressedFile.OpenAsync(FileAccessMode.ReadWrite)) { OutputText.Text += "All streams wired for decompression\n"; //解压 var bytesDecompressed = await RandomAccessStream.CopyAsync(decompressor, decompressedOutput); OutputText.Text += String.Format("Decompressed {0} bytes of data\n", bytesDecompressed); } OutputText.Text += "All done"; } catch (Exception ex) { OutputText.Text += ex.Message; } } private void Default_Click(object sender, RoutedEventArgs e) { DoWork(null); } private void Xpress_Click(object sender, RoutedEventArgs e) { DoWork(CompressAlgorithm.Xpress); } private void XpressHuff_Click(object sender, RoutedEventArgs e) { DoWork(CompressAlgorithm.XpressHuff); } private void Mszip_Click(object sender, RoutedEventArgs e) { DoWork(CompressAlgorithm.Mszip); } private void Lzms_Click(object sender, RoutedEventArgs e) { DoWork(CompressAlgorithm.Lzms); } }
效果图
未完待续,敬请期待...
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