用c#如何更改文件名与文件夹名

1.
File.Move(srcFileName,destFileName)
Directory.Move(srcFolderPath,destFolderPath)
2.
FileInfo file=new FileInfo(srcFileName);
file.MoveTo(destFileName);
DirectoryInfo folder=new DirectoryInfo(srcFolderPath);
folder.MoveTo(destFolderPath);

但是用第一种方法比较好,只节省构造对象时的一些开销

FileInfo inf=new FileInfo(@"e:\123.xml");
        inf.MoveTo(@"e:\1234.xml");


if ( System.Io.File.Exists( filename ) )
{
}
or

FileInfo fi = new FileInfo( fileName );
if ( fi.Exists )
{
}