Duplicate key exception from Entity Framework?

catch (UpdateException ex)
{
    SqlException innerException = ex.InnerException as SqlException;
    if (innerException != null && innerException.Number == ??????)
    {
        // handle exception here..
    }
    else
    {
        throw;
    }
}

Put the correct number at ?????? that corresponds to unique constraint violation (I don’t know it from the top of my head).