文件路径问题

1。     filename= "ErrorMessage.txt ";       得到//“C:\WINNT\system32\ErrorMessage.txt”
2。     得到www路径   (/)=(c:\inetpub\wwwroot\)
          filename=Server.MapPath( "/msg/ErrorMessage.txt ");         //c:\inetpub\wwwroot\msg\ErrorMessage.txt
          filename=Server.MapPath( "/ ")   + "msg/ErrorMessage.txt ";
          filename=Server.MapPath( "../msg/ErrorMessage.txt ");
3。   得到当前虚拟根目录的路径   (   ~/)
          filename=Server.MapPath( "~/msg/ErrorMessage.txt ");//D:\公司项目\PowerMis\Web\msg\ErrorMessage.txt
          filename=HttpRuntime.AppDomainAppPath;
4.     当前路径(相对)(   ./)
        filename=Server.MapPath( "./ErrorMessage.txt ");D:\公司项目\PowerMis\Web\     ErrorMessage.txt
        filename=Server.MapPath(Request.ApplicationPath);
        filename=Server.MapPath( ". ");
5       /Web
        filename=HttpRuntime.AppDomainAppVirtualPath;  
        filename=Request.ApplicationPath;