C# IO

流的分类

存取位置分类：
FileStream
MemoryStream
BufferedStream

读写类：
BinaryReader/BinaryWriter
TextReader/TextWriter

StreamReader/StreamWriter
StringReader/StringWriter

相互关系：

FileStream fin = new FileStream(@"Path", FileMode.Open, FileAccess.Read );
StreamReader brin = new StreamReader(fin, System.Text.Encoding.Default );

FileStream

• Seek
• Read

StreamReader

实例：new StreamReader(path, FileMode)

• ReadLine
• ReadToEnd
• Read
• Peek
• Close

StreamWriter

实例：new StreamWriter(path, FileMode, FileEncode)

• WriteLine
• Write
• Flush
• Close

using System;
using System.IO;
  
public class Logger 
{
    static void Main()
    {
        LogToFile( "msg", true, true );
    }
  
    public static string LogFile = @"c:\aaa.log";
  
    public static void LogToFile( string str, bool bWithTime, bool bAppendLineFeed)
    {
        if( str == null ) return;
  
        try
        {
            string fname = LogFile;
  
            if( fname == "" || fname == null ) return;
          
            StreamWriter writer = new StreamWriter( fname, true, System.Text.Encoding.Default );
            if( bWithTime )writer.WriteLine( "\r\n\r\n--------- " + DateTime.Now.ToString() );
  
            if( bAppendLineFeed ) writer.WriteLine( str );
            else writer.Write( str );
  
            writer.Close();
        }
        catch(Exception e )
        {
            Console.Write( e );
        }
    }
}

public class CopyFileAddLineNumber 
{
    public static void Main(string[] args) 
    {
        string infname = "CopyFileAddLineNumber.cs";
        string outfname = "CopyFileAddLineNumber.txt";
        if( args.Length >= 1 ) infname = args[0];
        if( args.Length >= 2 ) outfname = args[1];
  
        try 
        {
            FileStream fin = new FileStream( 
                infname, FileMode.Open, FileAccess.Read );
            FileStream fout = new FileStream(
                outfname, FileMode.Create, FileAccess.Write );
  
            StreamReader brin = new StreamReader( 
                fin, System.Text.Encoding.Default );
            StreamWriter brout  = new StreamWriter(
                fout, System.Text.Encoding.Default );
  
            int cnt = 0; // 行号
            string s = brin.ReadLine();
            while ( s != null ) 
            {
                cnt ++; 
                s = deleteComments(s);                        //去掉以//开始的注释
                brout.WriteLine(cnt + ": \t" + s );           //写出
                Console.WriteLine(cnt + ": \t" + s );     //在控制上显示
                s = brin.ReadLine();                      //读入
            }           
            brin.Close();               // 关闭缓冲读入流及文件读入流的连接.
            brout.Close();
        } 
        catch (FileNotFoundException) 
        {
            Console.WriteLine("File not found!" );
        } 
        catch (IOException e2) 
        {
            Console.WriteLine( e2 );
        }
    }
  
    static string deleteComments( string s ) //去掉以//开始的注释
    {
        if( s==null ) return s;
        int pos = s.IndexOf( "//" );
        if( pos<0 ) return s;
        return s.Substring( 0, pos );
    }
}

Serializble

• BinaryFormatter
• XmlFormatter

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
  
namespace SerializationTest
{
  [Serializable]
  class Book {
      public string name;
      //public double price;
      public int num=13; //如果book的版本变了，反序列化时，这个默认值不会被执行
      public string [] reader;
  
      override public string ToString(){
          return name + ":" //+ price 
              + ":" + string.Join(",",reader)
              + ":" + num;
      }
  }
  class Program
  {
      static void Main(string[] args)
      {
  
      }
  
      static void TestBinary()
      {
          BinaryFormatter formatter = new BinaryFormatter();
  
          //Serialization of String Object
          Book book = new Book();
          book.name = "学习C#";
          book.price = 123.45;
          book.reader = new string[]{ "张三", "李四", "王五"};
  
          FileStream stream = new FileStream("C:\\StrObj.t", FileMode.Create, FileAccess.Write ,
            FileShare.None);
          formatter.Serialize(stream, book);
          stream.Close();
  
          //Deserialization of String Object
          FileStream readstream = new FileStream("C:\\StrObj.t", FileMode.Open , FileAccess.Read ,
            FileShare.Read );
          Book book2 = (Book)formatter.Deserialize(readstream);
          readstream.Close();
          Console.WriteLine(book2);
          Console.ReadLine();
      }
  }
}

Directory，File

Directory，DirectoryInfo
File，FileInfo

FileSystemInfo 是 DirectoryInfo，FileInfo 的父类

FileInfo 实例信息包含：

• Name
• Extension
• FullName
• Length
• CreationTime
• LastAccessTime
• LastWriteTime
• DirectoryName
• Attributes

DirectoryInfo 实例信息包含：

• Name
• FullName
• CreationTime
• LastAccessTime
• LastWriteTime
• Parent
• Root

File 新建，复制，移动，删除文件：

• Create(filePath)
• Copy(filePath1,filePath2)
• Move(filePath1,filePath2)
• Delete(filePath1)
• Exists(filePath)
• CreateText(filePath);

Directory 新建，复制，移动，删除文件夹：

• CreateDirectory(dirPath)
• Move|Delete|Exists
• GetDirectories(dirPath)
• GetFiles(dirPath)

Path

Combine
GetDirectoryName
GetExtension
GetFileName
GetFileNameWithoutExtension
GetFullPath
GetPathRoot
GetTempFileName
GetTempPath

using System;
using System.IO;
class  ListAllFiles 
{
    public static void Main(string[] args)
    { 
        ListFiles( new DirectoryInfo( @"c:\workspace"));
    }
  
    public static void ListFiles( FileSystemInfo info )
    {
        if( ! info.Exists ) return;
  
        DirectoryInfo dir = info as DirectoryInfo;
        if( dir == null ) return; //不是目录
          
        FileSystemInfo [] files = dir.GetFileSystemInfos();
        for( int i=0; i<files.Length; i++)
        {
            FileInfo file = files[i] as FileInfo;
            if( file != null ) // 是文件
            {
                Console.WriteLine( 
                    file.FullName + "\t" + file.Length );
            }
            else    //是目录
            {
                ListFiles( files[i] );  //对于子目录,进行递归调用
            }
        }
    }
}