Question

I have written the following code:

//get the user from the DB
var tmpuser = _db.aspnet_Users.First(q => q.UserName == user.Identity.Name);

//list the direct connections to Verbond
List<Verbond> verb1 = tmpuser.UsersVerbondens
                             .Where(q => q.Schooljaar.Sch_Schooljaar == schooljaarparam)
                             .Select(q => q.Verbond)
                             .ToList();

//list the connected Facturatieverbonden
List<FacturatieVerbonden> verb2 = tmpuser.UsersFacturatieVerbondens
                                         .Where(q => q.Schooljaar.Sch_Schooljaar == schooljaarparam)
                                         .Select(q => q.FacturatieVerbonden)
                                         .ToList();

//loop through the facturatieverbonden and add their verbonds to the first list
foreach (FacturatieVerbonden v in verb2) {
    verb1.AddRange(v.Verbonds);
}

//make a distinct list
List<Verbond> test = verb1.Distinct().ToList();

So, Users can be connected to 0 or more facturatieverbonden and also can be connected to verbond.

A facturatieverbonden can have one or more verbond‘s under itself.

What I need is a list of all the verbond‘s the user is connected to, directly, or indirectly via the facturatieverbonden.

My code works but I don’t think it’s very efficient. Any hints on making it cleaner?

Answer 1

Your query isn’t very LINQy. Here’s a potential improvement:

           //list the direct connections to Verbond 
var test = (from q in tmpuser.UsersVerbondens
            where q.Schooljaar.Sch_Schooljaar == schooljaarparam
            select q.Verbond)
           //return distinct values
           .Union
           //list the connected Facturatieverbonden 
           (from q in tmpuser.UsersFacturatieVerbondens
            where q.Schooljaar.Sch_Schooljaar == schooljaarparam
            from v in q.FacturatieVerbonden.Verbonds
            select v)
           //return a List
           .ToList();

By making ToList the very last thing it does, the whole computation can be done in the database, avoiding all the intermediate lists.