The cast to value type 'Int32' failed because the materialized value is null

user_772987 0
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I have the following code. I'm getting error:

"The cast to value type 'Int32' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type."

when CreditHistory table has no records.

var creditsSum = (from u in context.User
                  join ch in context.CreditHistory on u.ID equals ch.UserID                                        
                  where u.ID == userID
                  select ch.Amount).Sum();

How can I modify the query to accept null values?

linq-to-entities entity-framework .net c#
8 Answers

Got this error in Entity Framework 6 with this code at runtime:

var fileEventsSum = db.ImportInformations.Sum(x => x.FileEvents)

Update from LeandroSoares:

Use this for single execution:

var fileEventsSum = db.ImportInformations.Sum(x => (int?)x.FileEvents) ?? 0

Original:

Changed to this and then it worked:

var fileEventsSum = db.ImportInformations.Any() ? db.ImportInformations.Sum(x => x.FileEvents) : 0;
user_38504050

I was also facing the same problem and solved through making column as nullable using "?" operator.

Sequnce = db.mstquestionbanks.Where(x => x.IsDeleted == false && x.OrignalFormID == OriginalFormIDint).Select(x=><b>(int?)x.Sequence</b>).Max().ToString();

Sometimes null is returned.

user_38200360
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