gistfile1.cs

public static DefaultSort GetDefaultSort<TModel, TProperty>(Expression<Func<TModel, TProperty>> expression, SortDirection direction)
{
    return new DefaultSort(EvaluateExpression(expression), direction);
}

private static string EvaluateExpression(LambdaExpression expression)
{
    var memberExpression = expression.Body as MemberExpression;
    return memberExpression == null ? null : memberExpression.Member.Name;
}