public void SourceManipulation() { var numbers = new RangeObservableCollection <int>(System.Linq.Enumerable.Range(1, 10).Select(i => i * 3)); using (var query = numbers.ActiveAll(i => i % 3 == 0)) { Assert.IsNull(query.OperationFault); Assert.IsTrue(query.Value); numbers[0] = 2; Assert.IsFalse(query.Value); numbers.RemoveAt(0); Assert.IsTrue(query.Value); --numbers[0]; Assert.IsFalse(query.Value); numbers.Clear(); Assert.IsTrue(query.Value); numbers.Add(7); Assert.IsFalse(query.Value); } }