Unit 14 Event Driven Programming Level 3 Computing Year 1 Lecturer: Julie Hodsdon

Last time Introduced the unit Introduced VB.NET’s Integrated Development Environment (IDE) Learnt features of event driven programming Created a simple form BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Unit Learning outcomes Understand the features of event driven programming Be able to use the tools and techniques of an event driven language Be able to design event driven applications Be able to implement event driven applications BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Assessment This unit is assessed by practical coursework designed around the criteria set by Edexcel. Three items of practical work (see wiki to be confirmed) Assignment 1 will be issued in October and is due before half term. BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Event Driven What does it mean? control flow of event driven programs is largely driven by external events (Mouse click, button press, keyboard input) BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Procedural Programming What does it mean? control flow is determined by the program structure (sequence, step by step) BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Today….. We will create: A simple GUI (graphical user interface) calculator A simple calculator using the console as our input /output device. Examine the code of both Evaluate the programs BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Visual Studio 2015 Let’s have a look at the IDE we will be using throughout this unit. On your computer, after you login, start Visual studio 2013 (vs2013). Then follow my video on You Tube so that you can work at the pace that suits you. https://www.youtube.com/watch?v=nHJpw-gnKlo BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Understanding the program Events Sub routines Variables BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Console based Calculator How will the program flow? Before we write the code, we need to design the application. Our design – What are the inputs. What are the outputs. What does the interface look like. You need to cater for adding, subtracting, multiplication and division between two numbers. BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Console based Calculator Task 1. In pairs – (use Microsoft word or Visio) Design a calculator application which will run in a command window. This should be in the form of a storyboard. You have 10 minutes. BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Time for a break? BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Console based Calculator In Visual Studio – create a new console project There is an example on the wiki that you can use BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Evaluation Which is better and why? (in your opinion) Task 2 – write an evaluation on - How does the console calculator compare to the GUI calculator? In terms of coding, User experience. Which is better and why? (in your opinion) You may want to use this as a start for Assignment 1 D1 BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

And finally……

Most, if not all, GUI systems and toolkits are designed to be event driven, meaning that the main flow of your program is not sequential from beginning to end. If you've never done GUI programming, this is one of the trickiest paradigm shifts. — Robin Dunn, speaking on GUI programming at OSCON2004 BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Hollywood Principle: "Don't call us; we'll call you. " Hollywood Principle: "Don't call us; we'll call you." ... You implement the interfaces, you get registered. You get called when the time is right. This requires a distinctly different way of thinking to that which is taught in introductory programming where the student dictates the flow of control. — Dafydd Rees, http://c2.com/cgi/wiki?HollywoodPrinciple The user dictates the flow of control BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming

Submit Task 1 and Task 2 to Moodle before next lesson Use the naming convention for TurnitIn as shown on the WIKI Enrolment code is: event BTEC Level 3 Year 1 - Unit 14 Event Driven lProgramming