C#基础：文件的读写

FileStream读写文件示例：

FileStream读：

byte[] byteData = new byte[200];
char[] charData = new char[200];
try
{
// 读取当前文件..表示上级目录
FileStream aFile = new FileStream("../../Program.cs", FileMode.Open);
//查找并从指定位置读取
aFile.Seek(174, SeekOrigin.Begin);
aFile.Read(byteData, 0, 200);
}
catch (IOException e)
{
WriteLine("An IO exception has been thrown!");
WriteLine(e.ToString());
ReadKey();
return;
}
//编码
Decoder d = Encoding.UTF8.GetDecoder();
d.GetChars(byteData, 0, byteData.Length, charData, 0);
WriteLine(charData);
ReadKey();

StreamFile写：

byte[] byteData;
char[] charData;
try
{
//打开文件，如果没有就创建新的
FileStream aFile = new FileStream("Temp.txt", FileMode.Create);
charData = "My pink half of the drainpipe.".ToCharArray();
byteData = new byte[charData.Length];
//编码
Encoder e = Encoding.UTF8.GetEncoder();
e.GetBytes(charData, 0, charData.Length, byteData, 0, true);
//查找位置，写入
aFile.Seek(0, SeekOrigin.Begin);
aFile.Write(byteData, 0, byteData.Length);
ReadKey();
}
catch (IOException ex)
{
WriteLine("An IO exception has been thrown!");
WriteLine(ex.ToString());
ReadKey();
return;
}

读StreamReader

string line;
try
{
// 用FileStream对象打开文件
FileStream aFile = new FileStream("Log.txt", FileMode.Open);
// 用StreamReader对象读取文件
StreamReader sr = new StreamReader(aFile);
line = sr.ReadLine();
// Read data in line by line.
while (line != null)
{
WriteLine(line);
line = sr.ReadLine();
}
sr.Close();
}
catch (IOException e)
{
WriteLine("An IO exception has been thrown!");
WriteLine(e.ToString());
}

写StreamWriter

try
{
// FileStream对象打开文件
FileStream aFile = new FileStream("Log.txt", FileMode.OpenOrCreate);
// StreamWriter对象写入文件
StreamWriter sw = new StreamWriter(aFile);
bool truth = true;
// Write data to file.
sw.WriteLine("Hello to you.");
// 文件写入的时间
sw.WriteLine($"It is now {DateTime.Now.ToLongDateString()} and things are looking good.");
sw.Write("More than that,");
sw.Write($" it's {truth} that C# is fun.");
sw.Close();
}
catch(IOException e)
{
WriteLine("An IO exception has been thrown!");
WriteLine(e.ToString());
ReadLine();
return;
}

GZipStream 读写压缩文件示例：

static void SaveCompressedFile(string filename, string data)//保存
{
FileStream fileStream =
new FileStream(filename, FileMode.Create, FileAccess.Write);
//压缩
GZipStream compressionStream =
new GZipStream(fileStream, CompressionMode.Compress);
StreamWriter writer = new StreamWriter(compressionStream);
writer.Write(data);
writer.Close();
}
static string LoadCompressedFile(string filename)//加载
{
FileStream fileStream =
new FileStream(filename, FileMode.Open, FileAccess.Read);
//解压
GZipStream compressionStream =
new GZipStream(fileStream, CompressionMode.Decompress);
StreamReader reader = new StreamReader(compressionStream);
string data = reader.ReadToEnd();
reader.Close();
return data;
}
static void Main(string[] args)
{
try
{
string filename = "fileStream.txt";
WriteLine(//using static System.Console
"Enter a string to compress (will be repeated 100 times):");
string sourceString = ReadLine();
StringBuilder sourceStringMultiplier =
new StringBuilder(sourceString.Length * 100);
for (int i = 0; i < 100; i++)
{
sourceStringMultiplier.Append(sourceString);
}
sourceString = sourceStringMultiplier.ToString();
WriteLine($"Source data is {sourceString.Length} bytes long.");
SaveCompressedFile(filename, sourceString);
WriteLine($"\nData saved to {filename}.");
FileInfo compressedFileData = new FileInfo(filename);
WriteLine($"Compressed file is {compressedFileData.Length} bytes long.");
string recoveredString = LoadCompressedFile(filename);
recoveredString = recoveredString.Substring(
0, recoveredString.Length / 100);
WriteLine($"\nRecovered data: {recoveredString}");
ReadKey();
}
catch (IOException ex)
{
WriteLine("An IO exception has been thrown!");
WriteLine(ex.ToString());
ReadKey();
}
}

FileSystem'Watcher监控文件系统：

简单的Design界面如下：

<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<Grid Margin="4">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBox Name="LocationBox" TextChanged="LocationBox_TextChanged" />//显示文件名字
<Button Name="BrowseButton" Grid.Column="1" Margin="4,0,0,0" Content="Browse..." Click="BrowseButton_Click" />//浏览文件button
</Grid>
<Button Name="WatchButton" Content="Watch!" Margin="4" Grid.Row="1" Click="WatchButton_Click" IsEnabled="False" />//监控button
<ListBox Name="WatchOutput" Margin="4" Grid.Row="2" />//文件更改时显示
</Grid>

代码隐藏文件如下：

private FileSystemWatcher watcher;
public MainWindow()
{
InitializeComponent();
watcher = new FileSystemWatcher();
watcher.Deleted += (s, e) => //删除
AddMessage($"File: {e.FullPath} Deleted");
watcher.Renamed += (s, e) => //重命名
AddMessage($"File renamed from {e.OldName} to {e.FullPath}");
watcher.Changed += (s, e) => //更改内容
AddMessage($"File: {e.FullPath} {e.ChangeType.ToString()}");
watcher.Created += (s, e) => //创建
AddMessage($"File: {e.FullPath} Created");
}
private void AddMessage(string message)
{
Dispatcher.BeginInvoke(new Action(
() => WatchOutput.Items.Insert(
0, message)));
}
private void BrowseButton_Click(object sender, RoutedEventArgs e)//浏览button的点击事件，打开windows浏览文件对话框
{
OpenFileDialog dialog = new OpenFileDialog();
if (dialog.ShowDialog(this) == true)
{
LocationBox.Text = dialog.FileName;
}
}
private void LocationBox_TextChanged(object sender, TextChangedEventArgs e)//文本更改事件
{
WatchButton.IsEnabled = !string.IsNullOrEmpty(LocationBox.Text);
}
private void WatchButton_Click(object sender, RoutedEventArgs e)//监控button点击事件，开始监控
{
watcher.Path = System.IO.Path.GetDirectoryName(LocationBox.Text);
watcher.Filter = System.IO.Path.GetFileName(LocationBox.Text);
watcher.NotifyFilter = NotifyFilters.LastWrite |
NotifyFilters.FileName | NotifyFilters.Size;
AddMessage("Watching " + LocationBox.Text);
// Begin watching.
watcher.EnableRaisingEvents = true;
}
}

C#基础：文件的读写

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