Question

• How do I utilize a ?: operator in the SELECT clause of a LINQ query? If this can’t be done, how can I emulate one? The goal is to get a CASE block in my select clause. As you might suspect, I’m getting an error: Invalid anonymous type member declarator. Anonymous type members must be declared with a member assignment, simple name or member access.

• Is this the proper way, or a sufficient way, to say ‘from a inner join i on a.ipid=i.id inner join u on i.uid=u.id’? If not, please provide one. Thanks.

  var query =     from a in db.tblActivities     from i in db.tblIPs     from u in db.tblUsers      select new {         u.UserName == null             ? i.Address             : u.UserName,         a.Request,         a.DateTime }; 

Answer 1

When creating an anonymous type (what you’re doing with the ‘new’ without specifying a type) you have to specify the member name for each property. From your example, it would look something like this: (also fixed your joins)

var query = from a in db.tblActivities             join i in db.tblIPs on a.ipid equals i.id             join u in db.tblUsers on i.uid equals u.id             select new {                UserName = (u.UserName ?? i.Address),                Request = a.Request,                Date = a.DateTime             }; 

You could probably do the UserName your way, too:

UserName = (u.UserName == null) ? i.Address : u.UserName, 

but the ?? operator is more concise. It’s similar to ‘isnull’ in SQL.