Dynamic Linq for dates - asp.net

Question

I want to build dynamic Linq. Following is my code which works fine for one date. But user can select many dates from calendar. And I need to make Linq for all those selected dates.
saleDate = calendarSales.SelectedDate;
List<SaleDetails> saleDetials = new List<SaleDetails>();
saleDetials = GetSaleDetails();
saleDetials.Where(sale => (Convert.ToDateTime(sale.DATE_TIME).Day == saleDate.Day &&
Convert.ToDateTime(sale.DATE_TIME).Month == saleDate.Month &&
Convert.ToDateTime(sale.DATE_TIME).Year == saleDate.Year)
).ToList();
How to update this query?

Answer 1

You have to build the predicate for your where clause dynamically.
Take a look at the predicatebuilder.
EDIT
Of cause PredicateBuilder supports AND and OR operators.
When using OR you have to start with the initial value of False:
// building the predicate
var pred = PredicateBuilder.False<SaleDetails>();
foreach (var date in MyDateList)
{
pred = pred.Or(sale => sale.DATE_TIME.Date == saleDate.Date);
}
// finally get the data and filter it by our dynamic predicate
List<SaleDetails> saleDetails = GetSaleDetails().Where(pred).ToList();

Answer 2

I'm not sure you need dynamic LINQ here. You should be able to check Where the sale matches Any of the selected dates, like so:
var saleDates = GetSelectedDate();
List<SaleDetails> saleDetials = new List<SaleDetails>();
saleDetials = GetSaleDetails();
saleDetials.Where(sale => saleDates.Any(date =>
(Convert.ToDateTime(sale.DATE_TIME).Day == date.Day &&
Convert.ToDateTime(sale.DATE_TIME).Month == date.Month &&
Convert.ToDateTime(sale.DATE_TIME).Year == date.Year)
)).ToList();
or checking on the Date property:
var saleDates = GetSelectedDate();
List<SaleDetails> saleDetials = new List<SaleDetails>();
saleDetials = GetSaleDetails();
saleDetials.Where(sale => saleDates.Any(date =>
Convert.ToDateTime(sale.DATE_TIME).Date == date.Date)).ToList();