public void Undo()
{
for (int i = 0; i <= _commands.Count; i++)
{
if (_current > 0)
{
INGCommand command = _commands[--_current] as INGCommand;
command.Undo();
}
}
}
public void Execute(INGCommand command)
{
try
{
command.Execute();
_commands.Add(command);
_current++;
}
catch (Exception ex)
{
Undo();
throw ex;
}
}