Linq Группировка

var groupQuery = from p in db.Distributions
                  group p by p.Name into groupName
                  select new { groupName.ToList() };

var groupQuery = db.Distributions.GroupBy(p => p.Name).ToList();

class GroupSample1
{
    // The element type of the data source.
    public class Student
    {
        public string First { get; set; }
        public string Last { get; set; }
        public int ID { get; set; }
        public List<int> Scores;
    }
 
    public static List<Student> GetStudents()
    {
        // Use a collection initializer to create the data source. Note that each element
        //  in the list contains an inner sequence of scores.
        List<Student> students = new List<Student>
        {
           new Student {First="Svetlana", Last="Omelchenko", ID=111, Scores= new List<int> {97, 72, 81, 60}},
           new Student {First="Claire", Last="O'Donnell", ID=112, Scores= new List<int> {75, 84, 91, 39}},
           new Student {First="Sven", Last="Mortensen", ID=113, Scores= new List<int> {99, 89, 91, 95}},
           new Student {First="Cesar", Last="Garcia", ID=114, Scores= new List<int> {72, 81, 65, 84}},
           new Student {First="Debra", Last="Garcia", ID=115, Scores= new List<int> {97, 89, 85, 82}} 
        };
 
        return students;
 
    }
 
    static void Main()
    {
        // Obtain the data source.
        List<Student> students = GetStudents();
 
        // Group by true or false.
        // Query variable is an IEnumerable<IGrouping<bool, Student>>
        var booleanGroupQuery =
            from student in students
            group student by student.Scores.Average() >= 80; //pass or fail!
 
        // Execute the query and access items in each group
        foreach (var studentGroup in booleanGroupQuery)
        {
            Console.WriteLine(studentGroup.Key == true ? "High averages" : "Low averages");
            foreach (var student in studentGroup)
            {
                Console.WriteLine("   {0}, {1}:{2}", student.Last, student.First, student.Scores.Average());
            }
        }
 
        // Keep the console window open in debug mode.
        Console.WriteLine("Press any key to exit.");
        Console.ReadKey();
    }
}

DataClasses1DataContext db = new DataClasses1DataContext(str);
 var myQuery = from p in db.Distributions
                          select new {p.Name };
 listBox1.ValueMember = "Name";
 listBox1.DataSource = groupQuery;

 DataClasses1DataContext db = new DataClasses1DataContext(str);
var groupQuery = from p in db.Distributions
                             group p by p.Name into groupName
                             select new { groupName.ToList() };
 listBox1.ValueMember = "Name";
 listBox1.DataSource = groupQuery;

NorthWindDataContex db = new NorthWindDataContex();
            var custs = (from customer in db.Customers
                         group customer by customer.City).ToList();
 
            listBox1.DisplayMember = "Key";
            listBox1.ValueMember = "Key";
            listBox1.DataSource = custs;

select new { groupName.ToList() };

NorthWindDataContex db = new NorthWindDataContex();
            var custs = (from customer in db.Customers
                         select new {Name = customer.City}).Distinct();
 
            listBox1.DisplayMember = "Name";
            listBox1.ValueMember = "Name";
            listBox1.DataSource = custs;