var total = query.Sum(x => (double?) x.Income); Replace double for single, int, long, etc.
By the way, the proper place to ask questions is the nhusers mailing list, not this one. RP On Sunday, March 30, 2014 4:42:24 PM UTC+1, Mouhong Lin wrote: > > Hi guys, > > I get an exception saying "Value cannot be null" when i execute this query > (NH 3.3.3): > > var total = query.Sum(x => x.Income); > > The exception happens when the query returns no result. > I found there's already a Jira issue about this: > https://nhibernate.jira.com/browse/NH-3113 > > But why won't fix? It's really not usable if this query throws exception. > In every application that need to do reporting will encounter this. > And this violate the semantic of the sum and linq to objects, right? > If this should throw exception, why query.Count() don't throws? > (I understand the technical reason of this, just saying why the semantic > of these are not consistent) > > If L2S or EF behaves the same, I think it's their bug. Not because it's a > good thing. > Workaounds like this "var sum = myQuery.Sum(x => (int?)x.Prop) ?? 0" make > my code really ugly. > > Ideas? > > > > ------------------------------ > Mouhong > > -- --- You received this message because you are subscribed to the Google Groups "nhibernate-development" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
