PortablePrism.Portable by Andrii Chebukin

<PackageReference Include="PortablePrism.Portable" Version="1.0.1" />

 CollectionExtensions

public static class CollectionExtensions
Class that provides extension methods to Collection
using System; using System.Collections.Generic; using System.Collections.ObjectModel; namespace Microsoft.Practices.Prism { public static class CollectionExtensions { public static Collection<T> AddRange<T>(this Collection<T> collection, IEnumerable<T> items) { if (collection == null) throw new ArgumentNullException("collection"); if (items == null) throw new ArgumentNullException("items"); foreach (T item in items) { collection.Add(item); } return collection; } } }