Visual Basic.NET How to Program (PDF)

476 Graphical User Interface Concepts: Part 1 Chapter 12
Outline
12.1 Introduction
12.2 Windows Forms
12.3 Event-Handling Model
12.4 Control Properties and Layout
12.5 Labels, TextBoxes and Buttons
12.6 GroupBoxes and Panels
12.7 CheckBoxes and RadioButtons
12.8 PictureBoxes
12.9 Mouse-Event Handling
12.10 Keyboard-Event Handling
Summary Terminology Self-Review Exercises Answers to Self-Review Exercises Exercises
12.1 Introduction
A graphical user interface (GUI) allows a user to interact visually with a program. A GUI
(pronounced “GOO-ee”) gives a program a distinctive “look” and “feel.” By providing different
applications with a consistent set of intuitive user-interface components, GUIs enable
users to spend less time trying to remember which keystroke sequences perform what
functions, freeing up time that can be spent using the program in a productive manner.
Look-and-Feel Observation 12.1
Consistent user interfaces enable a user to learn new applications more quickly. 12.1
As an example of a GUI, Fig. 12.1 depicts an Internet Explorer window in which various
GUI components have been labeled. Near the top of the window, there is a menu bar
containing menus, including File, Edit, View, Favorites, Tools and Help. Below the
menu bar is a set of buttons, each of which has a defined task in Internet Explorer. Below
these buttons lies a textbox, in which users can type the locations of World Wide Web sites
that they wish to visit. To the left of the textbox is a label that indicates the textbox’s purpose.
Scrollbars are situated on the far right and bottom of the window. Usually, scrollbars
are employed when a window contains more information than can be displayed in the
window’s viewable area. By clicking the scrollbars, the user can view different portions of
the window. These components form a user-friendly interface through which the user interacts
with the Internet Explorer Web browser.
GUIs are built from GUI components (which are sometimes called controls or widgets—short
for window gadgets). A GUI component is an object with which the user interacts
via the mouse or keyboard. Several common GUI components are listed in Fig. 12.2.
In the sections that follow, we discuss each of these GUI components in detail. The next
chapter explores the features and properties of more advanced GUI components.