C# Linq Group By on multiple columns [duplicate]

Question

public class ConsolidatedChild {     public string School { get; set; }     public string Friend { get; set; }     public string FavoriteColor { get; set; }     public List<Child> Children { get; set; } }  public class Child {     public string School { get; set; }     public string Name { get; set; }     public string Address { get; set; }     public string Friend { get; set; }     public string Mother { get; set; }     public string FavoriteColor { get; set; } } 

Given the two classes above, I would like to use LINQ to create a List from the List, grouped by the School, Friend and FavoriteColor properties. Is this possible with LINQ?

Please ignore the properties, the code has been written just to help with the question.

Answer 1

var consolidatedChildren =     from c in children     group c by new     {         c.School,         c.Friend,         c.FavoriteColor,     } into gcs     select new ConsolidatedChild()     {         School = gcs.Key.School,         Friend = gcs.Key.Friend,         FavoriteColor = gcs.Key.FavoriteColor,         Children = gcs.ToList(),     }; 

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var consolidatedChildren =     children         .GroupBy(c => new         {             c.School,             c.Friend,             c.FavoriteColor,         })         .Select(gcs => new ConsolidatedChild()         {             School = gcs.Key.School,             Friend = gcs.Key.Friend,             FavoriteColor = gcs.Key.FavoriteColor,             Children = gcs.ToList(),         });