（转自：http://www.csharpwin.com/csharpspace/6649r3960.shtml）

C#文件操作：C#追加文件

           StreamWriter sw = File.AppendText(

                Server.MapPath(".") + "\\myText.txt");

            sw.WriteLine("追逐理想"); 

            sw.WriteLine("kzlll"); 

            sw.WriteLine(".NET笔记"); 

            sw.Flush(); sw.Close();   

C#文件操作：C#拷贝文件 

            string OrignFile, NewFile; 

            OrignFile = Server.MapPath(".") + "\\myText.txt"; 

            NewFile = Server.MapPath(".") + "\\myTextCopy.txt"; 

            File.Copy(OrignFile, NewFile, true);  

C#文件操作：C#删除文件 

C#文件操作：C#移动文件   

            string OrignFile, NewFile; 

            OrignFile = Server.MapPath(".") + "\\myText.txt";

            NewFile = Server.MapPath(".") + "\\myTextCopy.txt"; 

            File.Move(OrignFile, NewFile);

C#文件操作：C#创建目录

               // 创建目录c:\sixAge   
            DirectoryInfo d = Directory.CreateDirectory("c:\\sixAge");   
            // d1指向c:\sixAge\sixAge1   
            DirectoryInfo d1=  d.CreateSubdirectory("sixAge1");   
            // d2指向c:\sixAge\sixAge1\sixAge1_1   
            DirectoryInfo d2=  d1.CreateSubdirectory("sixAge1_1");   
            // 将当前目录设为c:\sixAge   
            Directory.SetCurrentDirectory("c:\\sixAge");   
            // 创建目录c:\sixAge\sixAge2   
            Directory.CreateDirectory("sixAge2");   
            // 创建目录c:\sixAge\sixAge2\sixAge2_1   
            Directory.CreateDirectory("sixAge2\\sixAge2_1");