Win8Metro中文件读写删除与复制操作

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async3 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(byte[]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, IEnumerable lines);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 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！";

}

}