Question

I need to insert a new blank, but non null anonymous type into a list of other anonymous types returned by a linq query. Is that possible? All I can get are nulls

var something =
( from a in x.As
 where x != null
  join b in x.Bs
    on a.key equals b.key
select new
{
    a.prop1,
    a.prop2,
    b.prop1,
    b.prop2,
    b.prop3
}).ToList();

// insert blank
//something.InsertRange(0, something.DefaultIfEmpty());
//something.InsertRange(0, something.Take(0));
//?

Answer 1

I don’t know of a way to do it in a single query since the default for an anonymous type is null. What I would do is pre-create a “default” item and append it if necessary:

var blank = new {
                prop1 = default(string),  // can't use null 
                prop2 = default(string),  // because the type cannot be inferred
                prop3 = default(string),
                prop4 = default(string)
                };

var something = /*...*/.ToList();
if(!something.Any())
    something.Add(blank);

Note that as long as the field names match (in name and type) blank will be of the same anonymous type as the one created by the Linq query.