public void AlreadySetDoubleChangeEventArgs(double?oldValue, double?newValue1, double?newValue2) { ChangeEventArgs <double?> changeEventArgs1 = new ChangeEventArgs <double?>(oldValue); ChangeEventArgs <double?> changeEventArgs2 = new ChangeEventArgs <double?>(oldValue, newValue1); try { changeEventArgs1.SetNewValue(newValue2); Assert.Equal(newValue2, changeEventArgs1.NewValue); changeEventArgs2.SetNewValue(newValue2); } catch (Exception ex) { Assert.IsType <AlreadySetException <double?> >(ex); } }