/// <summary>
/// Constructs a BeforeTextBufferChangeUndoPrimitive.
/// </summary>
/// <param name="textView">
/// The text view that was responsible for causing this change.
/// </param>
/// <param name="undoHistory">
/// The <see cref="ITextUndoHistory" /> this primitive will be added to.
/// </param>
/// <exception cref="ArgumentNullException"><paramref name="textView"/> is null.</exception>
/// <exception cref="ArgumentNullException"><paramref name="undoHistory"/> is null.</exception>
public static BeforeTextBufferChangeUndoPrimitive Create(ITextView textView, ITextUndoHistory undoHistory)
{
if (textView == null)
{
throw new ArgumentNullException("textView");
}
if (undoHistory == null)
{
throw new ArgumentNullException("undoHistory");
}
// Store the ITextView for these changes in the ITextUndoHistory properties so we can retrieve it later.
if (!undoHistory.Properties.ContainsProperty(typeof(ITextView)))
{
undoHistory.Properties[typeof(ITextView)] = textView;
}
CaretPosition caret = textView.Caret.Position;
IMapEditToData map = BeforeTextBufferChangeUndoPrimitive.GetMap(textView);
int oldCaretIndex = BeforeTextBufferChangeUndoPrimitive.MapToData(map, caret.BufferPosition);
int oldCaretVirtualSpaces = caret.VirtualBufferPosition.VirtualSpaces;
VirtualSnapshotPoint anchor = textView.Selection.AnchorPoint;
int oldSelectionAnchorIndex = BeforeTextBufferChangeUndoPrimitive.MapToData(map, anchor.Position);
int oldSelectionAnchorVirtualSpaces = anchor.VirtualSpaces;
VirtualSnapshotPoint active = textView.Selection.ActivePoint;
int oldSelectionActiveIndex = BeforeTextBufferChangeUndoPrimitive.MapToData(map, active.Position);
int oldSelectionActiveVirtualSpaces = active.VirtualSpaces;
TextSelectionMode oldSelectionMode = textView.Selection.Mode;
if (oldCaretVirtualSpaces != 0 ||
oldSelectionAnchorIndex != oldCaretIndex ||
oldSelectionAnchorVirtualSpaces != 0 ||
oldSelectionActiveIndex != oldCaretIndex ||
oldSelectionActiveVirtualSpaces != 0 ||
oldSelectionMode != TextSelectionMode.Stream)
{
return(new GeneralBeforeTextBufferChangeUndoPrimitive
(undoHistory, oldCaretIndex, caret.Affinity, oldCaretVirtualSpaces, oldSelectionAnchorIndex,
oldSelectionAnchorVirtualSpaces, oldSelectionActiveIndex, oldSelectionActiveVirtualSpaces, oldSelectionMode));
}
else
{
return(new BeforeTextBufferChangeUndoPrimitive(undoHistory, oldCaretIndex, caret.Affinity));
}
}
/// <summary>
/// Do the action.
/// </summary>
/// <exception cref="InvalidOperationException">Operation cannot be redone.</exception>
public override void Do()
{
// Validate, we shouldn't be allowed to undo
if (!CanRedo)
{
throw new InvalidOperationException(Strings.CannotRedo);
}
// Set the new caret position and active selection
var view = this.GetTextView();
Debug.Assert(view == null || !view.IsClosed, "Attempt to undo/redo on a closed view? This shouldn't happen.");
if (view != null && !view.IsClosed)
{
DoMoveCaretAndSelect(view, BeforeTextBufferChangeUndoPrimitive.GetMap(view));
view.Caret.EnsureVisible();
}
_canUndo = true;
}
/// <summary>
/// Undo the action.
/// </summary>
/// <exception cref="InvalidOperationException">Operation cannot be undone.</exception>
public override void Undo()
{
// Validate that we can undo this change
if (!CanUndo)
{
throw new InvalidOperationException(Strings.CannotUndo);
}
// Restore the old caret position and active selection
var view = this.GetTextView();
Debug.Assert(view == null || !view.IsClosed, "Attempt to undo/redo on a closed view? This shouldn't happen.");
if (view != null && !view.IsClosed)
{
UndoMoveCaretAndSelect(view, BeforeTextBufferChangeUndoPrimitive.GetMap(view));
view.Caret.EnsureVisible();
}
_canUndo = false;
}