CS0004: Introduction to Programming

1. CS0004: Introduction to Programming Visual Studio 2010 and Controls

2. Review • Four Stages in a program • Read Input • Validate Input • Process Input • Output Result • An Algorithm is… • Astep-by-step procedure devised for the purpose of taking in data and producing the correct output. • What’s the difference between an algorithm and a program? • A program is the actual implementation of an algorithm in a programming language.

3. Review • When Developing a program in both the real world AND in this class, there are 6 steps • Analyze the problem • Plan a solution • Design an interface • Write the code • Test and debug • Document the program • (Not done in this class) Maintain the program

4. Review • An End User is… • The person whom the program was designed for. • A User-Interface is… • How the user interacts with your program. • A Bug is… • An error, flaw, mistake, failure, or fault in a computer program. • Documentation is… • Organizing all the material that describes the program. • Three models used to help develop an algorithm: • Flow Charts • Hierarchy Charts • Pseudocode

5. Visual Studio 2010 • Visual Studio is an Integrated Development Environment (IDE) • An IDE is a software application that provides comprehensive facilities to computer programmers for software development. • Visual Studio = IDE for developing Visual Basic Programs • Visual Basic = Programming Language • Visual Basic is designed to easily make user-friendly Graphical User Interfaces (GUIs). • A GUI allows the user to interact with programs in more ways than typing. They use graphical representations of objects instead of simply text. • GUIs include: • Icons • Buttons • Drop-down boxes • Etc.

6. Developing a User-Interface • After you have successfully developed an algorithm for your program you can develop a user-interface. • This is often NOT the first step in development in the real world, but for this class it often will be. • Visual Studio allows you to literally draw the interface, and it writes the code for you. • These interface objects will automatically have basic functionality, and can accept events. • This is not how it works with most other programming languages and IDEs. • You have to write the code for what happens on these events. • Important Note: Event-Driven Programming is fundamentally different than traditional Procedural Programming

7. Developing a Visual Basic Program • So, how to we add functionality to our interface? • Answer: We write Event Procedures. • An Event Procedure is a set of instructions to be executed when a certain event happens. • For example, we can write an Event Procedure for when we push an “OK” button. • Almost everything in Visual Basic is either an Event Procedure or used by an Event Procedure. • Here’s the basic steps when developing a Visual Basic Program: • Design the appearance that the user sees. • Determine the events that the controls on the window should respond to. • Write the event procedures for those events.

8. Programming Layer Model • Many event-driven programs can be divided into three important sections or layers: • Presentation Layer – Anything the user sees and how the user interacts with a program. • Logic Layer – How the program acts when it receives events. • Data Access Layer – Allows simple access to persistent storage (like a database). We probably won’t be doing this in this course. • It is important to separate the layers from each other as much as possible. • Why?

9. Programming Layer Model Presentation Layer Logic Layer Data Access Layer DB

10. How a Visual Basic Program is Run • When you run your Visual Basic program the following things happen: • Your program monitors the controls in the window to detect any event that a control can recognize (mouse movements, clicks, keystrokes, etc.) • When your program detects an event, it examines the code to see if you’ve written an even procedure for it. • If you have written an event procedure, the instructions in the procedure are executed and it goes back to step 1. • If you have not written an event procedure, it ignores the event and goes back to step 1.

11. Visual Studio Tutorial • New Project • On the opening screen click on “New Project” • Enter a name, a location for your project, and a solution name. • Click on “Windows Forms Application”. • Click the “OK” button. • Open an Existing Project • Click on “Open Project” • Navigate to you “.sln” file and double click on it. • Parts of the IDE: • Menu Bar – Has menus such as: File, Edit, View, Window, Project, Data, and Debug. • Toolbar – Holds buttons that perform common controls. • Document Window – Currently holding the Form Window. • Form Window – What your VB program will look like when you open it. • Properties Window – Used to change how objects look and react. • Solution Explorer – Shows files associated with the program. • Toolbox – Contains controls to put on your form.

12. Visual Studio Tutorial • Textbox • Creating • Click on the text box tool • Click on the form to create default sized text box • Click and drag on the form to create custom size text box • Click on the text box to select it. • Push the delete key while it is selected to delete it • Properties Window (F4, clicking on it, toolbar button) • Name • Changes what the text box is called • Text • Changes what text is in the text box when the text box first appears.

13. Visual Studio Tutorial • Button • Properties • Text • Access Key – Putting an “&” in front of the text will give it an access key. • If you press “Alt + the first character in front of the &” it will do the same as clicking the button. • Label • Properties • AutoSize – If true, the text property will decide how big the label is. If false, you can resize it. • Tab Order – Sets the order in which the controls are focused on when the user hits tab. • To set the tab order, number the TabIndex property of the controls starting at 0.

14. Visual Studio Tutorial • Debugging/Stop Debugging • When you hit the “Debug Button” (The green play button), your program will compile and display what it will do. • You can then test and debug your running program. • To stop debugging either close your program normally or press the “Stop Debugging” button (The blue stop button). • Save All – Saves all files associated with the project • Click on the “Save All” button (The one with three disks) on the toolbar. • Or click on “File” in the menu bar and then “Save All” in the menu.

15. Naming • The naming (value of the name property) of controls should indicate what it is and what it does. • The name should include both what the object is in the form of a prefix, and what is does or if it doesn’t do anything specific, what it is.

16. Alignment of Controls • Often you want your controls to be a comfortable distance away from each other and the edge of the form. Visual Studio makes it easy to do this. • When you drag a control toward the edge of the form or another control, a Proximity Line appears to ensure a comfortable distance is between the control and the other object. • When you drag a control in an area that is close to being either vertically or horizontally aligned with another control, a Snap Line appears to help align the controls.