TTMSFNCUndoManager Class
Undo/redo manager that captures JSON state snapshots of an object and restores them in response to undo and redo requests.
API unit family: TMSFNCUndo
Inherits from: TCollection
Syntax
TTMSFNCUndoManager = class(TCollection)
Properties
| Name | Description |
|---|---|
| MaxStackCount | Maximum number of undo steps retained in the stack. Defaults to 20; oldest entries are dropped when the limit is reached. |
| Stack | Provides indexed access to the raw undo stack entries. |
Methods
| Name | Description |
|---|---|
| CanRedo | Returns True when at least one state ahead of the current position is available to redo. |
| CanUndo | Returns True when at least one state earlier than the current position is available to undo. |
| ClearUndoStack | Removes all entries from the undo stack and records a fresh baseline state. |
| NextRedoAction | Returns the action name of the state that would be applied by the next redo, or an empty string if no redo is available. |
| NextUndoAction | Returns the action name of the state that would be restored by the next undo, or an empty string if no undo is available. |
| PushState | Captures the current object state as a new undo entry; any states ahead of the current position are discarded. |
| Redo | Re-applies the next state from the redo stack and moves the current position forward by one. |
| Undo | Restores the previous state from the undo stack and moves the current position back by one. |