有没有办法压扁.Net ILookup <TKey, TElement> 进入清单 <TElement> ？

Question

Is there a quick way to get a flattened List<TElement> from an ILookup<TKey, TElement> that was created from the IEnumerable<TElement> extension?

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Updated with example

List<int> list = new List<int>();
var lookup = list.ToLookup(key => key);
list = lookup.?? // How to convert the lookup back to the list

Answer 1

lookup.SelectMany( x => x ).ToList()

然而，向ILookup转换回来很可能会改变顺序。

Answer 2

Not sure if this is what you are after. For Dictionary<> to List<>

List<TElement> list iLookUp.Values.ToList<TElement>();

from List<> to Dictionary<>

var dict = list.Cast<TElement>().ToDictionary(t => t.Id, t => t.Description);