Getting Only The Top Row From Each Group

Question

I have some code that groups a table by "Value1" and some loops that add the top row of each group to a list. This is a pretty ugly way to do this, and I was wondering if I could replace one of the foreach loops with a couple more lines in my LINQ query? Problem is, I don't have the foggiest idea how to do this.

var Result = 
from a in DB.Table1
group new {Values = a} by a.Value1 into c
select new {everything = c};

foreach (var Row in Result)
{
    foreach (var RowAll in Row.Everything)
        {
        List.Add(new List<string>() {RowAll.Value1, RowAll.Value2})
        break;
    }
}

Answer 1

Use Enumerable.First:

var List =
    (from Row in Result
     let RowAll = row.Everything.First()
     select new List<string>() {RowAll.Value1, RowAll.Value2}
    ).ToList();

Or, combined with your original query:

var List =
    (from a in DB.Table1
     group a by a.Value1 into c
     select new List<string>() {c.Key, c.First().Value2}
    ).ToList();

Answer 2

Use FirstOrDefault:

var query = from row in result
           let rowAll = row.Everything.FirstOrDefault()
           where rowAll != null
           select new List<string> {rowAll.Value1, rowAll.Value2};

var list = query.ToList();

Rereading you first query I realised you are grouping on a property of 'a' so there should be no empty groupings. First() should be safe as in the other posters example.