Visual Basic 2008 Programming: Business Applications with a Design Perspective
Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9
Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Appendix A Appendix B Appendix C Home
Last change: February 13 2016 18:48:19.

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Chapter 2: Visual Basic Programming Concepts
Last change: February 13 2016 18:48:07.

Understanding the Integrated Development Environment

Take another look at the steps you just took to develop the Welcome project. When you were resizing the form, and bringing both the label and the button to the form, you were in the design phase of your project. This phase is called design time. At design time, you work with the visual aspect of your project. The elements that you bring from the Toolbox onto the form are called controls. When you run the project by clicking the Start button on the toolbar, your project enters run time. In this phase, the code in your project comes to life, responding to events triggered by either the user’s or the system’s actions. When you clicked the Say Welcome button, the button’s Click event occurred. The code you wrote in Sub Button1_Click was then triggered in response. The line

Label1.Text = “Welcome to Visual Basic!!!”

tells the computer to move the ”Welcome to Visual Basic!!!” text string to the Text property of Label1. The Text property of Label1 is then changed and displayed on the label. When your program quits, you still remain in the development environment, ready for another round of modification to the project.

Program Development in the Good Old Days

In the old DOS environment, when programs were developed in procedure-oriented languages such as COBOL, all the visual aspect of a program was written in code. Additional code was—as is now—also needed to handle computations. The code was written with a text editor and saved as a file. The file was then input into a language processor, recognized as a compiler that translated the source program into machine executable code (in machine language), which was saved as a separate file. This executable file was then run to produce the results that the developer desired. (Note: Quick Basic worked a bit differently.) In effect, a programmer had to work with three different programs at different phases of the program development activities to obtain results: an editor at design time, a compiler at compile time, and the compiled program at run time (see right side of Figure 1.1). You can imagine how long it could take (and how tedious it was) to develop a bug-free program that could be used formally for business data processing.

Program Development in the VS IDE

In contrast, when you are developing a program in VB.NET, all the activities in visual design, code editing, and testing can be carried out in a single environment. While you are entering code, the IDE checks for apparent syntax errors and also compiles your code. When you run your program, the IDE makes your program execute without having to leave the development environment and is thus recognized as the Integrated Development Environment.

Last change: February 13 2016 18:48:09.