List<T> Concatenation dynamically

I am trying to concate List<> as follows- 

 List<Student> finalList = new List<Student>();
 var sortedDict = dictOfList.OrderBy(k => k.Key);
 foreach (KeyValuePair<int, List<Student>> entry in sortedDict) {          
     List<Student> ListFromDict = (List<Student>)entry.Value;
     finalList.Concat(ListFromDict);
 }

But no concatenation happens. finalList remains empty. Any help?

Jon Skeet
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Other answers have explained why Concat isn't helping you - but they've all kept your original loop. There's no need for that - LINQ has you covered:

List<Student> finalList = dictOfList.OrderBy(k => k.Key)
                                    .SelectMany(pair => pair.Value)
                                    .ToList();

To be clear, this replaces the whole of your existing code, not just the body of the loop.

Much simpler :) Whenever you find yourself using a foreach loop which does nothing but build another collection, it's worth seeing whether you can eliminate that loop using LINQ.

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