Software Design

Name the controls with three-letter prefix that helps identify what kind of control is in use. Use unabbreviated words with mixed case to complete the name, eg frmPropertiesCheck. Table 1.1 below lists standard prefixes for commonly used controls.


What is Event-Driven Programming?

Whenever any user action occurs in an application, Windows generates one or more messages that are sent to the application. This is called Windows messaging. User actions are called events, like clicking a button that fires a click event in Visual Basic and if the user presses the spacebar, the KeyPress event is fired. The programmer must handle the event by writing code (explicit instructions) that specifies how to handle the user action or event. This code, called an event procedure or a method, is written in an object’s code window.

How to Run and Test Programs?

The easiest way to test is to simply run the program. The system then builds a solution by converting your code and form design into executable code. As a part of the build process, errors may be identified. Once the solution is built and contains no errors, you can then run it.

Program can be run with or without the Debugger. The Debugger is helpful in finding problems with the program code.


SUMMARY

• Microsoft Visual Basic .NET is a set of programming tools that allows you to create applications for the Windows operating systems and for Internet.
• Programs in Visual Basic are event-driven. User initiates an event by clicking the mouse or pressing a key.
• The code written by a programmer to respond to an event is called a method.
• The Solution Explorer lists all files and modules that make up an application. It may contain information about more than one project.
• A Toolbar provides easy access to frequently performed commands. A number of specialized toolbars can be displayed to make other commands readily available.
• The Toolbox initially contains many controls that you can add to your forms. More controls can be added to the Toolbox that offers greater capabilities.
• The Properties windows list the properties information for a selected form or object.
• Standard prefixes have been developed for naming commonly used controls.
• It is important to give descriptive name to all objects. Build the names with appropriate three-letters prefix followed by one or more words starting with uppercase letters. The word(s) should describe the control’s use.
• A Visual Basic project consists of all forms, controls, code, and other items that make up an application. Use the Solution Explorer to views those components.
• Programs in Windows are based on messages that generate events for the application. Each event executes code contained in the event’s method


Exercise

1. When a user clicks the mouse or keys in a letter it is called a(n) _____________.

2. Code executed when an even occurs is called a(n) ________________.

3. To run a program in Visual Basic, you can select an item from the ___________ menu.

4. An input box is used to collect ______________ from the user to use in the program.

5. One way to obtain “context-sensitive” help is to select a keyword, property, or control and press the _______________ key on the keyboard.

6. GUI stands for _______________________________________ .

7. IDE stands for _______________________________________ .

8. The form is sometimes called the _____________________ of a project, because the user interacts with the application through the form.

9. The Solution Explorer window lists all ____________ and ______________ used in the project or projects