PackageExplorerViewModel.PackageViewModel.AddFileToFolder C# (CSharp) Méthode

        private void AddFileToFolder(PackageFolder folder, string file)
        {
            if (folder == null) {
                string guessFolderName = FileHelper.GuessFolderNameFromFile(file);
                bool confirmed = UIServices.Confirm(
                    String.Format(CultureInfo.CurrentCulture, Resources.ConfirmToMoveFileIntoFolder, file, guessFolderName));

                if (confirmed) {
                    if (RootFolder.ContainsFolder(guessFolderName)) {
                        folder = (PackageFolder)RootFolder[guessFolderName];
                    }
                    else {
                        folder = RootFolder.AddFolder(guessFolderName);
                    }
                }
                else {
                    folder = RootFolder;
                }
            }

            folder.AddFile(file);
        }