how to rename folder at run time.

DirectoryInfo imageFolder = new DirectoryInfo(Server.MapPath("~/Gallary/") + str + "/Images/");
            string Imgpath = "~/Gallary/" + str + "/Images/";

            bool isImg = System.IO.Directory.Exists(Server.MapPath(Imgpath));
            if (isImg==true)
            {
                DirectoryInfo newimageFolder = new DirectoryInfo(Server.MapPath("~/Gallary/") + txtname.Text + "/Images/{0}");
                string newImgpath = "~/Gallary/" + txtname.Text + "/Images/";
                bool isnewImg = System.IO.Directory.Exists(Server.MapPath(newImgpath));
                if (!isnewImg)
                {                    
                    newimageFolder.Create();
                    Directory.Move(Imgpath, newImgpath);
                    xmldoc.Save(Server.MapPath("~/" + "XML/album.xml"));
                }                         
            }