User events.tips,tricks and sundry chris roebuck ni days 2013

NI Days 2013

User Events: tips, tricks and sundry

Chris Roebuck

Hello & Welcome

• Chris Roebuck (aka croebuck)

As a courtesy to others…….

Leave your smartphone switched ON

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Make your friends jealous you’re here learning cool new stuff and they’re not !!!

Lets give some credit….• “User events, tips, tricks and sundry “

– Presented by Jack Dunaway at the 2013 European CLA Summit held in Paris

• “Everything You wanted to know about events (but were afraid to ask)”– Presented by Norm Kirchner at NI Week 2013

Show of hands…….

I don’t need no stinkin’ events !

History Lesson

Before 6i the only real option was to “poll” the control values

Remember doing this ?

History Lesson 6.1

LabVIEW 6.1 quietly introduced the Event Structure and gaveus some limited access to static VI Server events

History Lesson 7 Express

Brought us “dynamic” event registration

History Lesson 8.0History Lesson 8.2

Brought us .net events & event callbacks

and now 2013

…and now we’ve got some new primitives and features likePriority events and the ability to flush the event queue

Syntax – Static Events (VI Server)

Statically bind an event “handler” structure to a VI Server event at edit time using the event configuration dialog

Syntax – Dynamic Events (VI Server)

Dynamically bind an event “handler” structure to a VI Server event at run time

Syntax – Dynamic / User / Custom Events“The Palette”

Publisher

Subscriber

Semantics

Demo’s & Myth Busting

Myth #1: Events are slow

Myth #2 : Events Can’t Handle Big Data

Myth #3 : Events Are Dangerous

Events For Messaging

Message 1

Message 2

Message 3

MSG Producer

MSG Consume

r

Publisher SubscriberSubscriber Producer Consumer

Events For Messaging

How do we do that ?

…..but what about objects?

Private & Public Events API

And fire it !!!

Obtain a reference to

the event

Summary

• Scalable (Actor Oriented Design ?)• Loosely Coupled (Reusable) Components • Testability• Easy to create an API (Private & Public Events)

Take Home Point

User Events are a lightweight, easy-to-use native feature with some really cool functionality.

SSBV use them a a primary way of performing intra-process communications.

They just got a whole lot better in LabVIEW 2013 so if you’ve dismissed them, take another look

c.roebuck@ssbv.com

@roebuckchris

www.walkingthewires.com

Want to talk some more ?