PrintingSystem.XlSheetCreated +=
                (sender, args) =>
                {
                    switch (args.Index)
                    {
                        case 0:
                            args.SheetName = "foo";
                            break;
                        case 1:
                            args.SheetName = "bar";
                            break;
                        case 2:
                            args.SheetName = "baz";
                            break;
                    }
                };