Group by in LINQ

Question

Let\'s suppose if we have a class like:

class Person { 
    internal int PersonID; 
    internal string car; 
}

I have a list of this class

Answer 1

First, set your key field. Then include your other fields:

var results = 
    persons
    .GroupBy(n => n.PersonId)
    .Select(r => new Result {PersonID = r.Key, Cars = r.ToList() })
    .ToList()