Win8Metro中,我们不能在向以前那样调用WIN32的API函数来进行文件操作,因此,下面就来介绍一下Win8 Metro中文件的读写操作。
1 Windows 8 Metro Style App中文件的操作都包含在Windows.Storage命名空间中，其中 包括StorageFolder,StorageFile,FileIO等类库 。
2 Win8文件的读写操作都是 异步方式进行的,因此要使用async
3 创建文件:
StorageFile storageFile=await Windows.Storage.KnownFolders.DocumentsLibrary.CreateFileAsync("1.txt",Windows.Storage.CreationCollisionOption.ReplaceExisting); 这里我们创建了一个1.txt的文档，如果已经存在这个文档，那么新建的文档将替换，覆盖掉旧文档。
由于文档读写是异步方式操作，因此，我们要将它放到async修饰的函数里才可以使用，具体如下：
private async void SelectImageOne(byt[] outArary){StorageFile storageFile=await Windows.Storage.KnownFolders.DocumentsLibrary.CreateFileAsync("1.txt",Windows.Storage.CreationCollisionOption.ReplaceExisting);await FileIO.WriteBytesAsync(storageFile, outArary);} 在上述的代码中，参数是我们要写入到文件“1.txt”里的内容，这里是一个byte[]数组。
4 写入文件：
如3中的代码所示await FileIO.WriteBytesAsync(storageFile, outArary);
写入文件的方法是FileIO中的write方法，这里一共有以下四种方法：
WriteBufferAsync(Windows.Storage.IStorageFile file, IBuffer buffer);WriteBytesAsync(Windows.Storage.IStorageFile file, byte[] buffer);WriteLinesAsync(Windows.Storage.IStorageFile file, IEnumerablelines);WriteLinesAsync(Windows.Storage.IStorageFile file, IEnumerable lines,UnicodeEncoding encoding);WriteTextAsync(Windows.Storage.IStorageFile file, string contents);WriteTextAsync(Windows.Storage.IStorageFile file, string contents, UnicodeEncoding encoding);
这里我们列举的是写入byte[]的方法。
5 打开文件：
StorageFile storageFile=await Windows.Storage.KnownFolders.DocumentsLibrary.CreateFileAsync("1.txt",Windows.Storage.CreationCollisionOption. OpenIfExists); 这里我们打开了一个名字为”1.txt”的文本文件。
6 读取文件：
在FileIO中有三种文件读取方法，分别读取不同的文件：
await FileIO.ReadTextAsync(Windows.Storage.IStorageFile file);await FileIO.ReadTextAsync(Windows.Storage.IStorageFile file, UnicodeEncoding encoding);//返回指定的文本编码格式await FileIO. ReadBufferAsync (Windows.Storage.IStorageFile file);await FileIO. ReadLinesAsync (Windows.Storage.IStorageFile file);await FileIO. ReadLinesAsync (Windows.Storage.IStorageFile file, UnicodeEncoding encoding);
这里我们以文本为例：string fileIContent = await FileIO. ReadTextAsync (storageFile);这样我们就返回了一个string文本。我们也可以通过流来读取文件：IBuffer buffer = await FileIO.ReadBufferAsync(storageFile);using (DataReader dataReader = DataReader.FromBuffer(buffer)){string fileContent = dataReader.ReadString (buffer.Length);}7 IBuffer, byte[], Stream之间的相互转换：StorageFile storageFile=await Windows.Storage.KnownFolders.DocumentsLibrary.CreateFileAsync("1.txt",Windows.Storage.CreationCollisionOption. OpenIfExists);IBuffer buffer = await FileIO.ReadBufferAsync(storageFile);byte[] bytes=WindowsRuntimeBufferExtensions.ToArray(buffer,0,(int)buffer.Length);Stream stream = WindowsRuntimeBufferExtensions.AsStream(buffer);另外一个实例：1.首先创建一个文件夹，在文件夹里创建文件 private async void CreateButton_Click(object sender, RoutedEventArgs e) { string name=FileName.Text; //创建文件的名称 folder =ApplicationData.Current.LocalFolder; StorageFolder tempFolder = await folder.CreateFolderAsync("Config",CreationCollisionOption.OpenIfExists); file =await tempFolder.CreateFileAsync(name,CreationCollisionOption.OpenIfExists); }2.在创建好的文件里，写入我们的数据，这里介绍三种写入文件的方式 private async void WriteButton_Click(object sender, RoutedEventArgs e) { string content = InputTextBox.Text.Trim(); ComboBoxItem item = WriteType.SelectedItem asComboBoxItem; //选择写入的方式 string type = item.Tag.ToString(); switch (type) { case"1": //以文本的方式写入文件 await FileIO.WriteTextAsync(file,content); break; case"2": //以bytes的方式写入文件 Encoding encoding = Encoding.UTF8; byte[] bytes = encoding.GetBytes(content); await FileIO.WriteBytesAsync(file,bytes); break; case"3": //以流的方式写入文件 IBuffer buffer = Convert(content); //将string转换成IBuffer类型的 await FileIO.WriteBufferAsync(file,buffer); break; } } 3.读取刚才写入文件里的数据，这里也介绍三种读取文件的方式 private async void ReadButton_Click(object sender, RoutedEventArgs e) { ComboBoxItem item = ReadType.SelectedItem asComboBoxItem; string type = item.Tag.ToString(); string content = string.Empty; switch (type) { case"1": //以文本的方式读取文件 content =await FileIO.ReadTextAsync(file); break; case"2": //以流的方式读取文件 IBuffer buffer = await FileIO.ReadBufferAsync(file); content = Convert(buffer); break; case"3": content =await Convert(); break; } ShowTextBox.Text = content; } private IBuffer Convert(string text) //将string转换成IBuffer类型的 { using (InMemoryRandomAccessStream stream = newInMemoryRandomAccessStream()) { using (DataWriter dataWriter = newDataWriter()) { dataWriter.WriteString(text); return dataWriter.DetachBuffer(); } } } private string Convert(IBuffer buffer) //将IBuffer转换成string类型的 { string text = string.Empty; using (DataReader dataReader=DataReader.FromBuffer(buffer)) { text = dataReader.ReadString(buffer.Length); } return text; } private async Task Convert() { string text=string.Empty; using (IRandomAccessStream readStream = await file.OpenAsync(FileAccessMode.Read)) { using (DataReader dataReader = newDataReader(readStream)) { UInt64 size = readStream.Size; if (size <= UInt32.MaxValue) { UInt32 numBytesLoaded = await dataReader.LoadAsync((UInt32)size); text = dataReader.ReadString(numBytesLoaded); } } } return text; }4.读取文件的属性 private async void ReadPropertyButton_Click(object sender, RoutedEventArgs e) { ComboBoxItem item = Files.SelectedItem asComboBoxItem; string name = item.Content.ToString(); StorageFolder tempFolder =await Windows.Storage.ApplicationData.Current.LocalFolder.GetFolderAsync("Config"); if (tempFolder != null) { file =await tempFolder.GetFileAsync(name); if (file != null) { StringBuilder builder = newStringBuilder(); builder.AppendLine("文件名称："+file.Name); builder.AppendLine("文件类型："+file.FileType); BasicProperties basic = await file.GetBasicPropertiesAsync(); builder.AppendLine("文件大小："+basic.Size+"bytes"); builder.AppendLine("上次修改时间："+basic.DateModified); builder.AppendLine("文件路径："+file.Path); List list = newList (); list.Add("System.DateAccessed"); list.Add("System.FileOwner"); IDictionary extra = await file.Properties.RetrievePropertiesAsync(list); var property = extra["System.DateAccessed"]; if (property != null) { builder.AppendLine("文件创建时间："+property); } property = extra["System.FileOwner"]; if(property!=null) { builder.AppendLine("文件所有者："+property); } DisplyProperty.Text = builder.ToString(); } } }5.复制删除文件 private async void OKButton_Click(object sender, RoutedEventArgs e) { try { ComboBoxItem item=FilesList.SelectedItem asComboBoxItem; string fileName = item.Content.ToString(); //获得选中的文件名称 int index=fileName.IndexOf('.'); string firstName = fileName.Substring(0,index); string type = fileName.Substring(index); StorageFolder tempFolder = await folder.GetFolderAsync("Config"); //文件在Config文件夹下放置着 file =await tempFolder.GetFileAsync(fileName); if (file == null) { Msg.Text ="文件不存在！"; return; } if (CopyoButton.IsChecked.Value) //判断进行复制还是删除 { StorageFile copy = await file.CopyAsync(tempFolder,firstName+"复制"+type,NameCollisionOption.ReplaceExisting); Msg.Text ="复制成功！！！"; } else { await file.DeleteAsync(); Msg.Text ="删除成功！！！"; } } catch { Msg.Text ="操作失败！"; } }