I'm going through the learning cliff of programming for a 4-series
processor with VS2019.? I always try to program my drivers using VS2008
so the code can be run on a 3-Series processor or a 4-Series processor.?
In this case I need VS2019's support for WebSockets.

To pass data back to a group of Simpl+ modules I would do the following
with VS2008:

???? public class SerialChangeEventArgs : EventArgs
???? {
???????? public string entity_id { get; set; }

???????? public SerialChangeEventArgs()
???????? {
???????? }

???????? public SerialChangeEventArgs(string entity_id)
???????? {
???????????? this.entity_id = entity_id;
???????? }
???? }

???? public static class SignalChangeEvents
???? {
???????? public static event SerialChangedEventHandler onSerialValueChange;

???????? public static void SerialValueChange(string entity_id)
???????? {
???????????? SignalChangeEvents.onSerialValueChange(new
SerialChangeEventArgs(entity_id));
???????? }
???? }

However, under VS2019 I get the following error:

Error??? CS0246??? The type or namespace name
'SerialChangedEventHandler' could not be found (are you missing a using
directive or an assembly reference?)

I have the same "using" directives that I have used with VS2008.

Any assistance would be greatly appreciated.

Thanks

Jay