Linq分组由多个列组成，并在group by子句之前从表中获取额外值

Question

I'm wondering if it's even possible here is some code sample:

I've a table named Sample :

| Id| Name| Address| ExtraColumn| ExtraColumn2|

Here is class :

public class Sample{
   public int Id{get;set;}
   public string Name{get;set;}
   public string Address{get;set;}
   public float ExtraColumn{get;set;}
   public float ExtraColumn2{get;set;}
}

What I have now:

Model.Sample.GroupBy(x => new {x.Name, x.Address}).Select(x => new {x.Key, Count = x.Count()});

But I need besides Key, values of ExtraColumn and ExtraColumn2 for each Sample entity in single database request .

So the question is: Is it even possible?

If so how to get it done?

Answer 1

If I have understood you correctly, this is what you want:-

Model.Sample.GroupBy(x => new {x.Name, x.Address})
            .Select(x => 
                    new 
                     {
                        Name = x.Key.Name, 
                        Address = x.Key.Address,
                        Count = x.Count(),
                        obj = x.ToList()
                     });

Here, obj will contain the List<Sample> in each group.