Question

I have some queries that look like this:

public List<AnObjectModel> GetObjectFromDB(TheParameters)
{
   using MyDataContext
   {
     var TheList = (....select new AnObjectModel()...).ToList();
     return new List<AnObjectModel>(TheList);
   }
}

And they work just fine.
My question is this: at the moment, I’m using var and then I’m doing a cast. Would doing this have any performance benefit?

   public List<AnObjectModel> GetObjectFromDB(TheParameters)
    {
       using MyDataContext
       {
         List<AnObjectModel> TheList = (....select new AnObjectModel()...).ToList();
         return TheList;
       }
    }

It would take me about 20 minutes to make the changes and I’m wondering if there’d be any difference.

Thanks.

Answer 1

You’re not using a cast – you’re creating a new list. That’s definitely pointless, given that you’ve already got a freshly-created List<T>. I would just write:

return (....select new AnObjectModel()...).ToList();

Or quite possibly:

var query = from ...
            select new AnObjectModel { ... };
return query.ToList();

That avoids having to bracket the query expression, which generally looks ugly.

Edit according to taste for layout, but definitely remove the redundant list creation.