Linq语句需要优化

Question

我写了以下代码:

//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();

因此,用户可以连接到0或更多facturatieverbonden,也可以连接到verbond.

A 本身facturatieverbonden可以有一个或多个verbond.

我需要的是一个verbond用户连接到的所有用户的列表,直接或间接通过facturatieverbonden.

我的代码有效,但我认为它不是很有效.任何关于使其清洁的提示？

Answer 1

你的查询不是很LINQy.这是一个潜在的改进:

           //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();

通过完成ToList最后的工作,整个计算可以在数据库中完成,避免所有中间列表.