| Count, Items | Number of sheets, and 1-based indexed access to each TXLSXWorksheet (default array property) |
| ActiveIndex | 0-based index of the sheet Excel activates on open; -1 when none is set yet. Note this is 0-based whilst IndexByName/Items/Duplicate are 1-based — subtract 1 when combining them |
| Add | Appends a new sheet, optionally with a name; overloads take no name or a WideString name |
| IndexByName, SheetByName, TryGetSheetByName | Look up a sheet by name; SheetByName returns nil and TryGetSheetByName returns False when not found |
| DeleteByName | Removes a sheet by name; returns False when no sheet had that name |
| Duplicate | Copies a sheet (cells, merges, sizing, freeze panes, view, protection, page setup, tab colour) within the same workbook; charts/images/tables/validations are not copied — see TXLSXWorksheet.CopyFrom |
| Clear | Removes every sheet from the collection |
This example adds a sheet, then finds and activates it by name (IndexByName is 1-based, ActiveIndex is 0-based)