/// <summary>
/// Adds a new changeset to the undo history. The change set will be added to the existing batch, if in a batch.
/// </summary>
/// <param name="changeSet">The ChangeSet to add.</param>
public void AddChange(ChangeSet changeSet) {
// System.Diagnostics.Debug.WriteLine("Starting AddChange: " + description);
// We don't want to add additional changes representing the operations that happen when undoing or redoing a change.
if (_isUndoingOrRedoing)
return;
// If batched, add to the current ChangeSet, otherwise add a new ChangeSet.
if (IsInBatch) {
foreach (var chg in changeSet.Changes) {
_currentBatchChangeSet.AddChange(chg);
//System.Diagnostics.Debug.WriteLine("AddChange: BATCHED " + description);
}
} else {
_undoStack.Push(changeSet);
OnUndoStackChanged();
//System.Diagnostics.Debug.WriteLine("AddChange: " + description);
}
// Prune the RedoStack
_redoStack.Clear();
OnRedoStackChanged();
}
/// <summary>
/// Tells the UndoRoot that it can stop collecting Changes into a single ChangeSet.
/// </summary>
public void EndChangeSetBatch() {
_isInBatchCounter--;
if (_isInBatchCounter < 0)
_isInBatchCounter = 0;
if (_isInBatchCounter == 0) {
_consolidateChangesForSameInstance = false;
_currentBatchChangeSet = null;
}
}
/// <summary>
/// Redo ChangeSets up to and including the lastChangeToRedo.
/// </summary>
public void Redo(ChangeSet lastChangeToRedo) {
if (IsInBatch)
throw new InvalidOperationException("Cannot perform a Redo when the Undo Service is collecting a batch of changes. The batch must be completed first.");
if (!_redoStack.Contains(lastChangeToRedo))
throw new InvalidOperationException("The specified change does not exist in the list of redoable changes. Perhaps it has already been redone.");
System.Diagnostics.Debug.WriteLine("Starting REDO: " + lastChangeToRedo.Description);
bool done = false;
_isUndoingOrRedoing = true;
try {
do {
var changeSet = _redoStack.Pop();
OnRedoStackChanged();
if (changeSet == lastChangeToRedo || _redoStack.Count == 0)
done = true;
changeSet.Redo();
_undoStack.Push(changeSet);
OnUndoStackChanged();
} while (!done);
} finally {
_isUndoingOrRedoing = false;
}
}
/// <summary>
/// Tells the UndoRoot that all subsequent changes should be part of a single ChangeSet.
/// </summary>
public void BeginChangeSetBatch(string batchDescription, bool consolidateChangesForSameInstance) {
// We don't want to add additional changes representing the operations that happen when undoing or redoing a change.
if (_isUndoingOrRedoing)
return;
_isInBatchCounter++;
if (_isInBatchCounter == 1) {
_consolidateChangesForSameInstance = consolidateChangesForSameInstance;
_currentBatchChangeSet = new ChangeSet(this, batchDescription, null);
_undoStack.Push(_currentBatchChangeSet);
OnUndoStackChanged();
}
}
