Namespace PSPDFKit.Document




Represents the source of a document, which may be a Windows.Storage.StorageFile, an Windows.Storage.Streams.IBuffer, or a IDataProvider.


The History API is disabled by default. It includes methods to undo and redo annotation operations: creation, updates and deletions may be reverted and restored by means of this API.

The implementation does not fully revert an annotation to its previous state:

  • The UpdatedAt field will have changed to the current time.

  • If an annotation deletion is undone, the restored annotation will have a different id than the original.

  • If an annotation deletion is undone, the restored annotation will appear at the front, regardless of its original stacking position.

  • Annotation changes that only affect the UpdatedAt property are not tracked, and the updated annotation is considered identical to the previous one in this case.

The feature only accounts for annotations modified locally, whether using the API or the toolbar UndoAsync and RedoAsync buttons.If an annotation is modified externally, by another Instant client, for example, undoing will not revert the annotation state to the one just before the external change, but to the previous to that one: external annotation operations are not undone, but overridden.

Annotation operations performed while the History API is disabled can also be considered external for that effect. This is also the case for annotation operations that result from Instant Comments changes, like deleting the last comment of a comment thread, which results on the comment marker being deleted, and which cannot therefore be undone. However, comment markers directly deleted with the API may be restored with its former comments.

Annotation presets are not restored by undo and redo operations.


Provides event information when history event occurs.



Type of history action.