/// <summary>
/// Invoked when the value of the referenced variable is changed.
/// </summary>
/// <param name="sender"></param>
/// <param name="args"></param>
void variable_ValueChanged(object sender, ValueChangedEventArgs args)
{
SetValue(variable.Value);
}
/// <summary>
/// Invoked when the value of source changes.
/// </summary>
/// <param name="sender"></param>
/// <param name="args"></param>
void source2Op_ValueChanged(object sender, ValueChangedEventArgs args)
{
Source2Changed((IEnumerable <TSource2>)args.OldValue, (IEnumerable <TSource2>)args.NewValue);
}