public static IQueryable<CustItemTrades> SeriesIdFilter(this
IQueryable<CustItemTrades> trades, List<short?> lastPriceDocs) =>
lastPriceDocs != null ? trades.Where(c => lastPriceDocs.Contains(c.SeriesId)) :
// what to return here if my List<short> == null
When my List is null it means that i dont have something to filter in my query what to return then?
I tried this way but it doesnt work
Enumerable.Empty<CustItemTrades>().AsQueryable();
>Solution :
Your approach does not work because Enumerable.Empty returns nothing, but you want to return all, if i have understood your requirement correctly.
When my List is null it means that i dont have something to filter in
my query
If you don’t have something to filter, then don’t filter.
public static IQueryable<CustItemTrades> SeriesIdFilter(this IQueryable<CustItemTrades> trades, List<short?> lastPriceDocs)
{
if(lastPriceDocs == null)
{
return trades;
}
return trades.Where(c => lastPriceDocs.Contains(c.SeriesId));
}
Don’t modify the query so that the Where matches always, simply return everything.