Question

I have a query to update a record; it looks somewhat like this:

public void SaveRecord(int TheUserID, Nullable<DateTime> TheDate,
                                                  Nullable<int> TheAction)
    {
      using DC...
      {
         var TheRecordToUpdate = (from....where ....
                                  select l).Single();

         TheRecordToUpdate.TheDate = TheDate;
         TheRecordToUpdate.TheAction = TheAction;

         TheDC.SubmitChanges();

The problem is that sometimes I supply null parameters and when that’s the case, I don’t want to change the field in the DB. How do I use the ?? operator in linq-to-sql when the parameter is null?

Thanks.

Answer 1

you can use the ?? operator

TheRecordToUpdate.TheDate = TheDate ?? TheRecordToUpdate.TheDate ;

or if you want to write it more explicitly

if (TheDate.HasValue){
    TheRecordToUpdate.TheDate = TheDate;
}

if TheRecordToUpdate.TheDate is not a nullable property however, you’ll have to write

if (TheDate.HasValue){
    TheRecordToUpdate.TheDate = TheDate.Value;
}