public void SourceManipulation() { var numbers = new ObservableDictionary <int, int>(Enumerable.Range(1, 10).ToDictionary(i => i, i => i * 3)); using var query = numbers.ActiveAll((key, value) => value % 3 == 0); Assert.IsNull(query.OperationFault); Assert.IsTrue(query.Value); numbers[1] = 2; Assert.IsFalse(query.Value); numbers.Remove(1); Assert.IsTrue(query.Value); --numbers[2]; Assert.IsFalse(query.Value); numbers.Clear(); Assert.IsTrue(query.Value); numbers.Add(11, 7); Assert.IsFalse(query.Value); }