UndoManager Properties and Methods Reference

Topic Overview

Purpose

This topic lists some of the important properties and methods of the UndoManager class.

In this topic

This topic contains the following sections:

UndoManager Class Reference
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UndoManager Class Reference

Introduction

The UndoManager class provides the functionality for performing undo/redo operations and maintaining the undo/redo history.

Performed operations are saved in history by adding UndoUnit instances to the UndoManager.

Note	Note The UndoManager class is not thread safe and it has to be used on a single thread.

Properties reference summary

The following table summarizes the purpose and functionality of the UndoManager class key properties.

Property	Description
CanRedo	Returns a boolean value indicating if there is an operation that can be redone. This property determines if there are UndoUnits in the RedoHistory.
CanUndo	Returns a boolean value indicating if there is an operation that can be undone. This property determines if there are UndoUnits in the UndoHistory.
Current	Returns a thread static singleton instance of an UndoManager. Another way to use the UndoManager class is to create a new instance. Each instance maintains its own history.
IsPerformingRedo	Returns a boolean value indicating if the manager is performing a redo operation. While `IsPerformingRedo` is True, the `UndoUnits` are added in the undo history because redo operations are performed.
IsPerformingUndo	Returns a boolean value indicating if the manager is performing an undo operation. While `IsPerformingUndo` is True, the `UndoUnits` are added in the redo history because undo operations are performed.
RedoHistory	Returns a read-only collection of the UndoHistoryItem instances in the redo history.
UndoHistory	Returns a read-only collection of the `UndoHistoryItem` instances in the undo history.

Methods reference summary

The following table summarizes the purpose and functionality of the UndoManager class key methods.

Method	Description
AddChange	Adds an `UndoUnit` to the history. There are several overloads of this method. One of them takes a given `UndoUnit` as an argument. The others take Action or Func<> instances that represents the methods to call when the operation is undone/redone.
AddCollectionChange	Adds an `UndoUnit` for the specified collection change to the undo history.
AddPropertyChange	Adds a PropertyChangeUndoUnitBase for the specified property value change to the undo history.
ClearHistory	Clears the undo and redo history.
ForEach	Enumerates the `UndoUnit` instances within the undo and redo history and invokes the provided `Action<UndoUnit>` delegate.
FromReference	Once an object is associated with the UndoManager, you can use this to obtain a reference to the UndoManager instance when it’s needed.
Redo	Performs one or more redo operations using the current history.
RegisterReference	Associates an object with an UndoManager instance.
Resume	Resumes the suspended recording of `UndoUnit` instances in the history.
StartTransaction	Creates and starts an UndoTransaction. This is useful when multiple operations have to be saved in the undo/redo history as one entry.
Suspend	Suspends the recording of `UndoUnit` instances in the history. You may need this method when initializing objects or collections or loading initial data. When the recording is suspended, calling the `Undo` or `Redo` methods will result in an exception.
Undo	Performs one or more undo operations using the current history.
UnregisterReference	Removes a registration created with `RegisterReference` method for an object that was registered with UndoManager instance.

Topic	Purpose
ObservableCollectionExtendedWithUndo Properties Reference	This topic lists some of the important properties and methods of the ObservableCollectionExtendedWithUndo class.
UndoHistoryItem Properties and Methods Reference	This topic lists the properties and methods of the UndoHistoryItem class.
UndoUnit Derived Classes, Properties and Methods Reference	This topic lists the derived classes and some of the important properties and methods of the UndoUnit class.
UndoUnitFactory Properties and Methods Reference	This topic lists some of the important properties and methods of the UndoUnitFactory class.

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