Microsoft Visual Basic 2010: Reloaded Fourth Edition Chapter One An Introduction to Visual Basic 2010

Microsoft Visual Basic 2010: Reloaded, Fourth Edition2 Objectives After studying this chapter, you should be able to: Create a Visual Basic 2010 Windows-based application Manage the windows in the Integrated Development Environment (IDE) Set the properties of an object Add a control to a form Use the Label, Button, and PictureBox tools Use the options on the Format menu

Microsoft Visual Basic 2010: Reloaded, Fourth Edition3 Objectives (cont'd.) Enter code in the Code Editor window Save a solution Start and end an application Print an application’s code and interface Write an assignment statement Print an application’s code and interface Close and open an existing solution Find and correct a syntax error

Visual Studio 2010 Visual Basic 2010 is an object-oriented programming language –Object: anything that can be seen, touched, or used –Class: a pattern used to create an object –Instance: an object created from a class; object is said to be instantiated Integrated Development Environment (IDE): –Contains all the tools and features needed to create, run, and test programs –Includes Visual Basic, Visual C++, Visual C#, and Visual F# Microsoft Visual Basic 2010: Reloaded, Fourth Edition4

5 Visual Studio 2010 (cont'd.) Application: program or suite of programs Windows-based application: –Has a Windows user interface –Runs on a personal computer User interface: what the user sees and interacts with when using an application Web-based application: –Has a Web user interface –Runs on a server –Accessed with a computer browser

Microsoft Visual Basic 2010: Reloaded, Fourth Edition6 Creating a Visual Basic 2010 Windows Application Windows applications consist of solutions, projects, and files Solution: a container that stores projects and files for an entire application Project: a container that stores files associated with a specific portion of the solution A solution may contain one or more projects

Microsoft Visual Basic 2010: Reloaded, Fourth Edition7 Solutions, Projects, and Files (cont'd.) Figure 1-1: Illustration of a solution, project, and file

Microsoft Visual Basic 2010: Reloaded, Fourth Edition8 Starting Microsoft Visual Studio 2010 Figure 1-2: How to start Visual Studio 2010 or Visual Basic 2010 Express Edition

Microsoft Visual Basic 2010: Reloaded, Fourth Edition9 Figure 1-3: Visual Studio 2010 Professional startup screen

Microsoft Visual Basic 2010: Reloaded, Fourth Edition10 Figure 1-4: Visual Basic 2010 Express startup screen

How to Create a Visual Basic 2010 Windows Application Microsoft Visual Basic 2010: Reloaded, Fourth Edition11 Figure 1-5: How to create a Visual Basic 2010 Windows application

How to Create a Visual Basic 2010 Windows Application (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition12 Figure 1-5: How to create a Visual Basic 2010 Windows application (cont’d.)

How to Create a Visual Basic 2010 Windows Application (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition13 Figure 1-6: Options dialog box

How to Create a Visual Basic 2010 Windows Application (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition14 Figure 1-7: Completed New Project dialog box in Visual Studio 2010

How to Create a Visual Basic 2010 Windows Application (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition15 Figure 1-8: Completed New Project dialog box in Visual Basic 2010 Express Edition

How to Create a Visual Basic 2010 Windows Application (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition16 Figure 1-9: Solution and Visual Basic Project

Managing the Windows in the IDE Microsoft Visual Basic 2010: Reloaded, Fourth Edition17 Figure 1-10: How to manage the windows in the IDE

The Windows Form Designer Window Windows Form Designer window: –Allows you to create (design) the GUI Graphical user interface (GUI): –What the user sees and interacts with Windows Form object (or form): –Foundation for the user interface –Add other objects such as buttons/text boxes to form –Title bar with caption and Minimize, Maximize, and Close buttons –Tab at top of designer window has Form1.vb [Design] Microsoft Visual Basic 2010: Reloaded, Fourth Edition18

The Windows Form Designer Window (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition19 Figure 1-11: Windows Form Designer window

Microsoft Visual Basic 2010: Reloaded, Fourth Edition20 The Solution Explorer Window Solution Explorer window: –Displays a list of projects contained in this solution –Displays the items contained in each project Figure 1-12: Solution Explorer window

Microsoft Visual Basic 2010: Reloaded, Fourth Edition21 The Solution Explorer Window (cont'd.) Source file: a file containing program instructions Code: program instructions Form file: a file containing code associated with a Windows form Give each form file a meaningful name using the Properties window

Microsoft Visual Basic 2010: Reloaded, Fourth Edition22 The Properties Window Properties: a set of attributes that determine an object’s appearance and behavior Properties window: displays properties of selected object Default property values are assigned when an object is created

Microsoft Visual Basic 2010: Reloaded, Fourth Edition23 The Properties Window (cont'd.) Figure 1-13: Properties window showing the Form1.vb file’s properties

Microsoft Visual Basic 2010: Reloaded, Fourth Edition24 The Properties Window (cont'd.) Properties window includes an Object box and a Properties list Object box: –Located immediately below Properties window title bar –Contains the name of the selected object Properties list: –Left column displays names of properties Use the Alphabetical or Categorized buttons to sort the display of properties –Settings box: Right column containing the current value of each property

Properties of a Windows Form Microsoft Visual Basic 2010: Reloaded, Fourth Edition25 Figure 1-14: Properties window showing a partial listing of the form’s properties

Microsoft Visual Basic 2010: Reloaded, Fourth Edition26 Properties of a Windows Form (cont'd.) Class definition: block of code that defines the attributes and behaviors of an object –All class definitions are contained in namespaces Namespace: defines a group of related classes Dot member access operator: the period that separates words in an object’s name to indicate a hierarchy of namespaces Name property: used to refer to an object in code –Give each object a meaningful name

Microsoft Visual Basic 2010: Reloaded, Fourth Edition27 Properties of a Windows Form (cont'd.) Pascal case: –First letter of each word in the name is uppercase –First part of name is object’s purpose –Second part of name is object’s class Text property: controls the caption displayed on form’s title bar StartPosition property: determines the form’s position on the screen when application starts Font: general shape of characters in text –Recommended font is Seqoe UI font Point: a measure of font sizes; one point = 1/72 inch

Microsoft Visual Basic 2010: Reloaded, Fourth Edition28 The Toolbox Window Toolbox: –Contains objects that can be added to other objects, such as a form –Each tool has an icon and a name to identify it –Each tool represents a class from which objects, called controls, can be created Controls: –Objects displayed on a form –Represented as icons in the toolbox Controls on a form can be selected, sized, moved, deleted, locked in place on the form and unlocked

Microsoft Visual Basic 2010: Reloaded, Fourth Edition29 Figure 1-15: Toolbox window

The Toolbox Window (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition30 Figure 1-16: How to add a control to a form

The Toolbox Window (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition31 Figure 1-17: How to manipulate the controls on a form

Microsoft Visual Basic 2010: Reloaded, Fourth Edition32 The Label Control Label control: –Displays text that user cannot edit –Used as “prompts” to explain controls or display output –Name should end with “Label” Control names use camel case Camel case: lowercase first word; uppercase first letter of each subsequent word in the name Not necessary to assign meaningful names for labels used as prompts because they are never used in code Labels used for output should have meaningful names

The Label Control (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition33 Figure 1-18: Wizard application’s user interface

Microsoft Visual Basic 2010: Reloaded, Fourth Edition34 The Button Control Button control: –Performs an immediate action when clicked –Its name should end with “Button” Text property: specifies the text that appears on the button’s face

The Picture Box Control Picture box control: used to display an image on a form Image property: specifies the image to display SizeMode property: handles how the image will be displayed –Settings: Normal, StretchImage, AutoSize, CenterImage, or Zoom Microsoft Visual Basic 2010: Reloaded, Fourth Edition35

Using the Format Menu Format menu: provides options for manipulating controls on the form –Align option: aligns two or more controls by left, right, top, or bottom borders –Make Same Size option: makes width and/or height of two or more controls the same –Center in Form option: centers controls horizontally or vertically on the form Multi-select controls by clicking the first, then using Ctrl-click for each additional control –First control selected is the reference control Its size/position is used to adjust the others Microsoft Visual Basic 2010: Reloaded, Fourth Edition36

The Code Editor Window Events: user actions while program is running –Examples: clicking, double-clicking, scrolling Event procedure: set of instructions to be processed when an event occurs –Tells the object how to respond to an event Code editor window: used to enter event procedure’s code Microsoft Visual Basic 2010: Reloaded, Fourth Edition37

The Code Editor Window (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition38 Figure 1-19: How to open the Code Editor window

The Code Editor Window (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition39 Figure 1-20: Code Editor window

Microsoft Visual Basic 2010: Reloaded, Fourth Edition40 The Code Editor Window (cont'd.) Class statement: used to define a class –Begins with Public Class –Ends with End Class Class Name list box: lists the names of objects (controls) included in the user interface Method Name list box: lists the events to which the selected object is capable of responding When you select a control from the Class Name list box and a method name, a code template for the event appears in the Code Editor window Syntax: rules of the language

Microsoft Visual Basic 2010: Reloaded, Fourth Edition41 The Code Editor Window (cont'd.) Keyword: a word with special meaning in a programming language Event code template has a procedure header and a procedure footer Event’s procedure header: –Begins with keywords Private Sub –Procedure name includes object name and event name –Handles clause indicates for which objects’ events this code will execute Sub procedure: block of code that performs a task

The Code Editor Window (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition42 Figure 1-21: Code template for the exitButton’s Click event procedure

Microsoft Visual Basic 2010: Reloaded, Fourth Edition43 The Me.Close() Instruction Me.Close() instruction: closes the current form at run time –If the current form is the only form, the application is terminated Me keyword: refers to the current form Method: predefined VB procedure that can be invoked (called) when needed Sequential processing: each line is executed in sequence –Also called a sequence structure

Microsoft Visual Basic 2010: Reloaded, Fourth Edition44 The Me.Close() Instruction (cont'd.) Figure 1-22: Me.Close() instruction entered in the Click event procedure

Microsoft Visual Basic 2010: Reloaded, Fourth Edition45 Saving a Solution An asterisk appears on the designer and Code Editor tabs if a change was made since the last time the solution was saved Figure 1-23: How to save a solution

Microsoft Visual Basic 2010: Reloaded, Fourth Edition46 Starting and Ending an Application Startup form: the form to be displayed when the application starts Figure 1-24: How to specify the startup form

Starting and Ending an Application (cont'd.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition47 Figure 1-25: Project Designer window

Microsoft Visual Basic 2010: Reloaded, Fourth Edition48 Starting and Ending an Application (cont'd.) Figure 1-26: How to start an application

Microsoft Visual Basic 2010: Reloaded, Fourth Edition49 Starting and Ending an Application (cont'd.) Figure 1-27: Result of starting the Wizard Viewer application

Microsoft Visual Basic 2010: Reloaded, Fourth Edition50 Starting and Ending an Application (cont'd.) When you start a VB application, the IDE creates an executable file Executable file: –Can be run outside of Visual Studio 2010 –Has a file extension of.exe –Stored in the project’s bin\Debug folder

Microsoft Visual Basic 2010: Reloaded, Fourth Edition51 Starting and Ending an Application (cont'd.) Figure 1-25: How to end an application

Microsoft Visual Basic 2010: Reloaded, Fourth Edition52 Assigning a Value to a Property During Run Time Properties window is used to set property values at design time Assignment statement: assigns a value to a variable or property of a control –Used to set property values at run time String: zero or more characters enclosed in quotation marks Assignment operator: the = sign Value of the expression on the right of the = sign is assigned to the object and property on the left of the = sign

Microsoft Visual Basic 2010: Reloaded, Fourth Edition53 Using an Assignment Statement (cont'd.) Figure 1-29: Assignment statements entered in the Code Editor window

Printing the Code and User Interface Microsoft Visual Basic 2010: Reloaded, Fourth Edition54 Figure 1-30: How to print the code and interface during design time

Microsoft Visual Basic 2010: Reloaded, Fourth Edition55 Closing the Current Solution Closing a solution closes all projects and files in that solution –You are prompted to save any files that have unsaved changes Figure 1-31: How to close a solution

Microsoft Visual Basic 2010: Reloaded, Fourth Edition56 Opening an Existing Solution Only one solution can be open at any one time If a solution is already open, opening a different one will close the currently open solution Figure 1-32: How to open an existing solution

Coding Errors Bug: an error in a program’s code Debugging: the process of locating and correcting bugs in a program Syntax error: occurs when you break one of the programming language’s rules –Most syntax errors are caused by typing errors Rest the mouse pointer on the mistyped instruction to see details about the error Microsoft Visual Basic 2010: Reloaded, Fourth Edition57

Microsoft Visual Basic 2010: Reloaded, Fourth Edition58 Coding Errors (cont’d.) Figure 1-33: Syntax error in the exitButton’s Click event procedure

Microsoft Visual Basic 2010: Reloaded, Fourth Edition59 Coding Errors (cont’d.) Figure 1-34: Syntax error message

Coding Errors (cont’d.) Syntax errors should be corrected before starting an application If you start an application with a syntax error, a dialog box appears –Click No to open the Error List window Microsoft Visual Basic 2010: Reloaded, Fourth Edition60 Figure 1-35: Dialog box

Coding Errors (cont’d.) Microsoft Visual Basic 2010: Reloaded, Fourth Edition61 Figure 1-36: Result of starting an application that contains a syntax error

Programming Tutorial 1 Microsoft Visual Basic 2010: Reloaded, Fourth Edition62 Figure 1-54: Result of starting the Wizard application

Programming Tutorial 2 Microsoft Visual Basic 2010: Reloaded, Fourth Edition63 Figure 1-67: Result of clicking the Abby button

Programming Example Microsoft Visual Basic 2010: Reloaded, Fourth Edition64 Figure 1-68: User interface

Summary Object-oriented programming language allows programmers to use objects to accomplish a goal Object: can be seen, touched, or used and has attributes that control its appearance and behavior Class: a pattern from which an object can be created Applications created in Visual Studio 2010 are composed of solutions, projects, and files Windows Form Designer window: used to create GUI applications Microsoft Visual Basic 2010: Reloaded, Fourth Edition65

Summary (cont'd.) A form is the foundation for the user interface Windows Form object is instantiated from the Windows Form class Solution Explorer window: displays names of projects and files in the solution Properties window: lists an object’s properties All class definitions are contained in namespaces System.Windows.Forms namespace contains definition of the Windows Form class and class definitions for objects added to a form Microsoft Visual Basic 2010: Reloaded, Fourth Edition66

Summary (cont'd.) Name property: used to refer to an object in code Text property of a form: specifies the text to be displayed in the title bar of the form and in the taskbar when running Form’s StartPosition property sets the position of the form when it first appears at run time Recommended font is Segoe UI in 9-point size Toolbox: contains tools for creating the GUI A control’s Text property value is displayed inside the control Microsoft Visual Basic 2010: Reloaded, Fourth Edition67

Summary (cont'd.) Controls on a form can be selected, sized, moved, deleted, or locked at design time Label control: contains text that a user cannot edit Button control: performs an immediate action when clicked Picture box control: displays an image on a form Format menu provides options for aligning and sizing controls on a form Event procedure: the code that tells an object how to respond to an event Microsoft Visual Basic 2010: Reloaded, Fourth Edition68

Summary (cont'd.) Use the Class Name and Method Name list boxes to select an object and event to code Code Editor: provides code templates for each object’s event procedures Me.Close( ) instruction: can terminate an application Computer automatically creates an executable file when you start a Visual Basic application in the IDE Use an assignment statement to assign a value to a property during run time Microsoft Visual Basic 2010: Reloaded, Fourth Edition69

Summary (cont'd.) You should print your application’s code and its user interface Closing a solution closes all projects and files in it The process of locating and correcting errors (bugs) in a program is called debugging Microsoft Visual Basic 2010: Reloaded, Fourth Edition70