LINQ OrderBy on inner object's property -
below hierarchies , required function public class friend { public string name { get; set; } public list<message> messages { get; set; } } public class message { public string text { get; set; } public datetime time { get; set; } } now required function: public list<string> whatsapp(list<friend> friends) { throw new notimplementedexception(); } i need list of friend names in descending order of there message time stamp. whats app or other im matter. i getting feeling can done in 1 or 2 lines using linq since new linq, unable drill down problem. thanks in advance help. if idea order last (i.e. max) message timestamp, following should job: return friends.orderbydescending(f => f.messages.max(m => (datetime?)m.time)) .select(f => f.name) .tolist(); casting datetime? needed avoid exception when there no messages friend. in general when need order parent having multiple children based on chi
