/// <summary>
/// Performs the 'Undo' action of the most recently added command to the system.
/// This command will then be moved to the redo stack so that it can later be redone
/// if the command supports it.
/// </summary>
public void UndoCommand()
{
if (mUndoStack.Count == 0)
{
throw new InvalidOperationException("There are no commands to be undone");
}
IVEFCommand cmd = mUndoStack.Pop();
cmd.Undo();
mRedoStack.Push(cmd);
FireStateChanged();
}
/// <summary>
/// Undoes the top most command on the undo stack and removes it from the system. The command
/// does not transfer to the redo stack.
/// </summary>
public void UndoAndPopCommand()
{
if (mUndoStack.Count == 0)
{
throw new InvalidOperationException("There are no commands to be undone");
}
IVEFCommand cmd = mUndoStack.Pop();
cmd.Undo();
cmd.Dispose();
// NOTE: We do not push the command onto the redo stack. It just vanishes
FireStateChanged();
}
