How can I include one expression in another expression?

Question

I have a DateRange class that I\'d like to apply to an IQueryable as a where predicate, automatically using the begin and end dates and automatically using an open or closed int

Answer 1

You'll have to hand-craft dateField >= BeginDate using Expression class methods.

(...)
    if (BeginInclusive)
    {
        var greaterOrEqual =
            Expression.Lambda>(
                Expression.GreaterThanOrEqual(
                    dateField.Body,
                    Expression.Constant(BeginDate)),
                dateField.Parameters);

        result = result.Where(greaterOrEqual);
    }
(...)

Similarly for the other cases.