using System; using System.Collections.Generic; namespace YABA.Common.Extensions { public static class DictionaryExtensions { public static void AddRange(this Dictionary source, Dictionary collection) { if (collection == null) { throw new ArgumentNullException("Collection is null"); } foreach (var item in collection) { if (!source.ContainsKey(item.Key)) { source.Add(item.Key, item.Value); } } } } }