public IUndoUnit UseRedo()
{
IUndoUnit obj = null;
if (_currentItem != null)
{
if (_position == EnumUndoStackPosition.AtRedo)
{
if (_currentItem.Previous != null)
{
_currentItem = _currentItem.Previous;
obj = _currentItem.Value.RedoObject;
}
}
else
{
obj = _currentItem.Value.RedoObject;
_position = EnumUndoStackPosition.AtRedo;
}
}
return(obj);
}
public IUndoUnit UseUndo()
{
IUndoUnit obj = null;
if (_currentItem != null)
{
if (_position == EnumUndoStackPosition.AtRedo)
{
obj = _currentItem.Value.UndoObject;
_position = EnumUndoStackPosition.AtUndo;
}
else
{
if (_currentItem.Next != null)
{
_currentItem = _currentItem.Next;
obj = _currentItem.Value.UndoObject;
}
}
}
return(obj);
}
public void AddUndoEntity(UndoEntity entity)
{
cutoff();
if (_currentItem != null)
{
if (_position == EnumUndoStackPosition.AtUndo)
{
RemoveFirst();
}
else
{
if (entity.UndoObject is SizeUndo && _currentItem.Value.UndoObject is SizeUndo)
{
if (((SizeUndo)entity.UndoObject).Key == ((SizeUndo)_currentItem.Value.UndoObject).Key)
{
RemoveFirst();
}
}
}
}
this.AddFirst(entity);
_currentItem = this.First;
_position = EnumUndoStackPosition.AtRedo;
}
