Biz.Managers.MediaMapfileManager.DeleteUnusedFiles C# (CSharp) Method

        private void DeleteUnusedFiles(string oldMapfile, Mapfile newMapfile)
        {
            // Need Remove unused files.
            Mapfile mapfile = JsonConvert.DeserializeObject<Mapfile>(oldMapfile);

            foreach (var a in mapfile.Files)
            {
                int s = newMapfile.Files.Where(f => f.FileName == a.FileName).Count();
                if (s == 0)
                {
                    var filepath = this.constants.LocalMediaPath + string.Format(@"lesson_{0}\{1}", this.baseModule.Id, a.FileName);
                    File.Delete(filepath);
                }
            }
        }