C#读写文件

（1）静态类File:

a) Byte[] bytes;
    File.WriteAllBytes(pathname, bytes);
b) String[] lines;
    File.WriteAllLines(pathname, lines, encode);
c) String text;
    File.WriteAllText(pathname,text,encode);

（2）FileStream       

// 主要用于读写二进制文件数据，可以读写任何文件

a) FileStream fs = new FileStream(PathName, FileMode,FileAccess, FileShare);
    fs.Write(bytes, offset, count);
    fs.Close();
b) FileInfo fi = new FileInfo(PathName);
    FileStream fs = fi.Open(…) / fi.OpenRead(…) / fi.OpenWrite(…);
    //FileStream fs = File.Open(…) / File.OpenRead(…) / File.OpenWrite(…);
    fs.Close();

（3）StreamWriter

// 专用于读写文本文件，也可不局限于文件

a)   StreamWriter sw = new StreamWriter (PathName);

a1)  StreamWriter sw = new StreamWriter (PathName, Append, Encode);

a2)  StreamWriter sw = new StreamWriter (Stream);

a3)  FileStream fs = new FileStream(PathName, FileMode, FileAccess, FileShare);
       StreamWriter sw = new StreamWriter (fs);

a4)  FileInfo fi = new FileInfo(PathName);
       StreamWriter sw = fi.CreateText();

b)   sw.Write(…) / sw.WriteLine(…);
c)   sw.Close();