(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
string delFile = Server.MapPath(".") + "\myTextCopy.txt";
File.Delete(delFile); 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:sixAgesixAge1
DirectoryInfo d1= d.CreateSubdirectory("sixAge1");
// d2指向c:sixAgesixAge1sixAge1_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:sixAgesixAge2
Directory.CreateDirectory("sixAge2");
// 创建目录c:sixAgesixAge2sixAge2_1
Directory.CreateDirectory("sixAge2\sixAge2_1");