There is no separate method for renaming the files and folders in c#. But we can achieve this by using Move method which is in File and Directory class.

Note: Please add System.IO namespace.

Renaming a File in C#

string path = Server.MapPath("~");
 string Fromfile = path + "\\[Foldername] \\" +[Filename];
string Tofile = path + "\\[Foldername]\\" +[Filename];
 File.Move(Fromfile, Tofile);

Renaming a Folder in C#

string path = Server.MapPath("~") ;
string Fromfol = "\\[Foldername] \\";
string Tofol = "\\[Foldername] \\";
Directory.Move(path + Fromfol , path + Tofol);