IUndoManager

Remarks

A control finds a manager rather than owning one. CodeBuffer argues the point and is right: undo belongs to the application, because it has to interleave with everything else — a rename that touched three files, a refactor, a move — and a stack inside a text control can only ever undo typing. What the argument does not settle is where the control looks, and until this existed the answer was nowhere, so a dialog's text box had no ⌘Z in any Vixen application including the editor.

⚠ Nearest wins, and nothing is a real answer. The lookup walks the element's ancestors and then the document, which is AppKit's NSResponder.undoManager with the ceremony removed. A field in a dialog with no document behind it finds nothing, registers nothing, and leaves ⌘Z to whatever else was listening — which is the right behaviour and is what keeps a text field from shadowing an application's own Undo.

⚠ Closures, not commands. An edit is two delegates. There is no interface for a caller to implement, no reflection and nothing to register (ADR-002); an implementation that already has a command stack — the editor's — adapts by wrapping its own command in the pair.

Fields and properties (3)

• bool CanUndo

  Whether there is anything to take back.

• bool CanRedo

  Whether there is anything to put back.

• bool IsPerforming

  Whether an undo or a redo is running right now.

Methods (3)

• void Register(string name, Action undo, Action redo)

  Records something that has already happened.

• bool Undo()

  Takes back the most recent edit.

• bool Redo()

  Puts back the most recently undone edit.

Used by (12)

• ControllerVixen.Ui.Tests
• IResponderVixen.Ui
• TextFieldVixen.Ui.Controls
• UiDocumentVixen.Ui
• UiElementVixen.Ui
• UndoCommandsVixen.Ui
• UndoManagerVixen.Ui
• ActiveDocumentUndoVixen.Editor.App
• CommandStackVixen.Editor.Core
• CommandStackUndoManagerTestsVixen.Editor.Core.Tests
• EditorApplicationVixen.Editor.App
• EditorUndoManagerTestsVixen.Editor.App.Tests