/// <summary>
/// Handles a change to the undo manager for a given dependency object.
/// </summary>
/// <param name="dependencyObject">The target object for this attached property.</param>
/// <param name="dependencyPropertyChangedEventArgs">The event parameters.</param>
private static void OnUndoManagerChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
{
// This will remove the previous UndoManager from the object. Note that an old UndoManager must be removed from the class before a new one can be
// added, otherwise the events will still be connected to the old manager after the new one is set.
if (dependencyPropertyChangedEventArgs.OldValue is UndoManager)
{
// This is the 'UnDo' manager for the old scope.
UndoManager undoManager = dependencyPropertyChangedEventArgs.OldValue as UndoManager;
// There is also a specific handler for the particulars of a given class (TextBox, CheckBox, etc.). To save time, a mapping is used to find an
// interface to the methods that handle the particulars of each class. An entry must be made in this map for any new user interface elements
// not covered by default by this class.
IUndo iUndo;
if (undoManager.TypeUndoMap.TryGetValue(dependencyObject.GetType(), out iUndo))
{
iUndo.Unregister(dependencyObject);
}
}
// This will connect a User Interface Element to an UndoManager. The UndoManager will be hooked into the elements events and when the control's
// content is changed, entries will be made in a stack that keeps track of the operations. This stack is integrated with all the other elements in
// the scope of this UndoManager so that actions are 'Undone' in the order they were added to the UndoManager in this scope.
if (dependencyPropertyChangedEventArgs.NewValue is UndoManager)
{
// This is the 'UnDo' manager for the new scope.
UndoManager undoManager = dependencyPropertyChangedEventArgs.NewValue as UndoManager;
// There is also a specific handler for the particulars of a given class (TextBox, CheckBox, etc.). To save time, a mapping is used to find an
// interface to the methods that handle the particulars of each class. An entry must be made in this map for any new user interface elements
// not covered by default by this class.
IUndo iUndo;
if (undoManager.TypeUndoMap.TryGetValue(dependencyObject.GetType(), out iUndo))
{
iUndo.Register(dependencyObject);
}
}
}
public UndoBase(UndoManager undoManager)
{
// Initialize the object.
this.undoManager = undoManager;
}
/// <summary>
/// Creates an object that manages the Undo/Redo logic that is particular to this control.
/// </summary>
/// <param name="undoManager">An object that coordinates all the undo/redo actions in a scope.</param>
public ToggleButtonUndo(UndoManager undoManager)
: base(undoManager)
{
// Initialzie the object
this.isUndoing = false;
}
/// <summary>
/// Set accessor for the UndoScope attached property.
/// </summary>
/// <param name="dependencyObject">The target object for this attached property.</param>
/// <param name="undoManager">The value for the attached property.</param>
public static void SetUndoScope(DependencyObject dependencyObject, UndoManager undoManager)
{
// This method shouldn't do anything more than set the attached property as XAML bypasses this accessor.
dependencyObject.SetValue(UndoScopeProperty, undoManager);
}
/// <summary>
/// Creates an object that manages the Undo/Redo logic that is particular to this control.
/// </summary>
/// <param name="undoManager">An object that coordinates all the undo/redo actions in a scope.</param>
public RichTextBoxUndo(UndoManager undoManager) : base(undoManager)
{
}
/// <summary>
/// Creates an object that manages the Undo/Redo logic that is particular to this control.
/// </summary>
/// <param name="undoManager">An object that coordinates all the undo/redo actions in a scope.</param>
public TextBoxBaseUndo(UndoManager undoManager) : base(undoManager)
{
}
/// <summary>
/// Creates an object that manages the Undo/Redo logic that is particular to this control.
/// </summary>
/// <param name="undoManager">An object that coordinates all the undo/redo actions in a scope.</param>
public SelectorUndo(UndoManager undoManager) : base(undoManager)
{
// Initialzie the object
this.isUndoing = false;
}