Transcript Bradley - University of South Carolina

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1-1
Chapter
1
Introduction to Visual
Basic.NET 2005
McGraw-Hill
© 2006 The McGraw-Hill Companies, Inc. All rights reserved.
Chapter Objectives (1 of 2)
 Describe the process of visual program design and
development
 Explain the term object-oriented programming
 Explain the concepts of classes, objects, properties,
methods, and events
 List and describe the three steps for writing a Visual
Basic project
 Describe the various files that make up a Visual Basic
project
1-3
Chapter Objectives (2 of 2)
 Identify the elements in the Visual Studio
environment
 Define design time, run time, and debug time
 Write, run, save, print, and modify your first Visual
Basic project
 Identify syntax errors, run-time errors, and logic
errors
 Use Auto Correct to correct syntax errors
 Look up Visual Basic topic in Help
1-4
Writing Windows Applications with VB
(1 of 2)
 Windows Graphical User (GUI) Interface
 Defines how elements look and function
1-5
Writing Windows Applications with VB
(2 of 2)
Windows are called forms
Elements are called
controls and are added
using a toolbox
1-6
Programming Languages-Procedural,
Event Driven and Object Oriented
 Procedural—Cobol, Fortran, Basic
 Program specifies exact sequence of all operations
 Event Driven (VB 6.0 and previous)
 Contain some elements of Object oriented programming but
not all
 Object Oriented Programming (OOP) (VB .NET)
 User controls sequence
 Click event
 Double Click event
 Change event
1-7
The Object Model
(1 of 2)
In VB you will work with objects, which have properties,
methods, and events. Each object is based on a class.
 Objects equate to Nouns
 Forms are windows
 Controls are components contained inside a form
 Properties equate to Adjectives
 Color or size of a Form
 Methods are like Verbs
 Typical methods include Close, Show and Clear
1-8
Object Model
(2 of 2)
 Events occur when the user takes action
 User clicks a button, User moves a form
 Classes are templates used to create a new object
 Classes contain the definition of all available properties,
methods, and events
 Each new object created is based on a class
 Creating three new buttons makes each button a instance
of the Button class
1-9
Object Model Analogy
 Class = automobile
 Properties = make, model, color, year
 Object = each individual car
 Object is also an Instance of the automobile class
 Methods = start, stop, speedup, slowdown
 Events = car arrives, car crashes
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Visual Studio .NET
 Included in Visual Studio .NET 2005





Visual Basic (can also be purchased separately)
Visual C++
C# (C sharp)
J# (J sharp)
.NET 2.0 Framework
 Visual Studio .NET Editions




Standard
Professional
Enterprise Developer
Enterprise Architect
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Writing Visual Basic Projects
There is a three-step process when writing a Visual Basic
application—you set up the user interface, define the
properties and then create the code
 Planning
1. Design the User Interface
2. Plan the Properties
3. Plan the Basic Code; follow the language syntax rules; use
pseudocode (English expression or comment describing
action) then you move on to
 Programming (and use the same three step process)
1. Define the User Interface
2. Set the properties
3. Write the Basic code
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VB Application Files
 One Solution File—think of
one solution file equals one project
.sln
 Solution User Options File
.suo
 Form Files
.vb
 Resource File for the Form
.resx
 Project Files
.vbproj
 Project User Options File
.vbproj.user
 Application configuration File
.app.config
Once a project is run several more files are created by the
system. The only file that is opened directly is the solution file.
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Visual Studio Environment
The Visual Studio environment is where you create and
test your projects-in Visual Studio it is called an
 Integrated Development Environment (IDE)
 consists of various tools including:
 Form Designer
 Editor for entering code
 Compiler
 Debugger
 Object Browser
 Help facility
1-14
Default Environment Settings
Visual Studio 2005
provides a new option
that allows the
programmer to select the
default profile for the IDE
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The IDE Initial Screen
The Visual
Studio IDE with
the Start Page
open, as it first
appears in
Windows XP,
without an open
project.
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IDE Main Window
Toolbars
Document Window
Form Designer
Solution Explorer Window
Properties Window
Toolbox
Help
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ToolBox
You can scroll to view
more controls
To sort the tools in the
toolbox:
•Right-click the toolbox and
select
•Sort Items Alphabetically
from the context menu
(shortcut menu).
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Modes
 Design Time--used when designing the user interface
and writing code
 Run Time--used when testing and running a project
 Break Time--if/when receiving a run-time error or
pause error
“Look at the Title Bar”
1-19
Writing Your First Visual Basic Project
Setting Up the Project
Hello World Project
1
2
3
1-20
Planning the Project
 Design the user interface
 Set up the form
 Resize the form
 Place a label and a button
control on the form using the
toolbox
 Lock the Controls in place
 After the user interface is
designed, the next step is to
set the properties
1-21
Setting Properties
 Label 1
Name
Text
messageLabel
leave blank
 Button 1
Name
Text
pushButton
Push Me
 Button 2
Name
Text
exitButton
Exit
 Form
Name
Text
helloForm
Hello World by
your name
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Setting the Form Properties
 The default startup
object is Form1
 The name of the form
should always be
changed to adhere to
naming rules
 The properties window
shows the files
properties
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Writing the Code
 While the project is running the user can perform
actions
 Each action by the user causes an event to occur
 Write code for the events you care about; the
events you want to respond to with code
 Code is written as event procedures
 VB will ignore events for which you do not write
code
 VB will automatically name event procedures as the
object name, an underscore(_) and the name of the
event
1-24
More on Writing the Code
 When writing the code for your first project you will use
the following:
 Remark Statement
 Assignment Statement
 Ending a Program
 Editor Window
1-25
Remark Statement
 Also known as Comment, used for
documentation; every procedure should begin
with a remark statement providing explanation
 Non-executable
 Automatically colored Green in Editor
 Begins with an apostrophe ( ' )
 On a separate line from executable code
 At the right end of a line of executable code
'Display the Hello World message.
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Assignment Statement
 Assigns a value to a property or variable
 Operates from right to left- the value appearing on the
right side of the equal sign is assigned to the property
named on the left of the equal sign
 Enclose text strings in quotation marks (" ")
messageLabel.Text=" Hello World "
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Ending a Program
 Methods always have parentheses (this will help you
distinguish them from Properties which never have parentheses)
 To execute a method of an object you write:
Object.Method()
 Current Form may be referenced as Me
Me.Close( )
1-28
Editor Window
 Declarations Section
 Class list
 Method list
1-29
Run, Save, Modify, Print, Test, Debug and
Execute
 Run Project
 Debug Menu, Start
 Start
 Start Without Debugging




(F5)
(CTRL+F5)
Save Project - File Menu, Save All
Modify Project if needed
"Help is always available from the
Print the Code
Help Menu or by pressing F1."
Correct any Errors and Rerun
 When you start executing your program, the first step is
called compiling, which means that the VB statements are
converted to Microsoft Intermediate Language (MSIL). Your
goal is to have no errors during the compile process: a
clean compile.
1-30
Print the Code
 File Menu, Print
 Prints complete code listing
 Uses arrow symbol to denote line continuation
1-31
Finding and Fixing Errors
 Syntax Errors
 Breaks VB’s rules for punctuation, format or spelling
 Smart editor finds most syntax errors, compiler finds the rest
 The editor identifies a syntax error with a squiggly blue line
and you can point to an error to pop up the error message.
 You can display the Error List window and line numbers in the
source code to help locate the error lines.
 Run-Time Errors
 Statements that fail to execute such as impossible arithmetic
operations
 Logic Errors
 Project runs but produces incorrect results
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Naming Rules and Conventions
 Have a set of standards and always follow them
 No spaces, punctuation marks or reserved words
 Use camel casing
 Examples
 messageLabel
 exitButton
 dataEntryForm
 paymentAmountTextBox
1-33
Recommended Naming Conventions for
VB Objects
Object Class
Example
Form
dataEntryForm
Button
exitButton
Label
totalLabel
TextBox
paymentAmountTextbox
Radio button
boldRadiobutton
CheckBox
printSummaryCheckBox
Horizontal Scroll Bar
rateHorizontalScrollBar
Vertical Scroll Bar
temperatureVerticalScrollBar
PictureBox
landscapePictureBox
ComboBox
bookListComboBox
ListBox
ingredientsListBox
SoundPlayer
introPageSoundPlayer
1-34
Visual Studio Help Additional Info (1 of 2)
 Visual Studio has an extensive Help facility,
 Filter MSDN help to display VB topics only
 Run MSDN from hard drive, CD or Web
 You can access MSDN on the Web at
http://msdn.microsoft.com
 The Help system display is greatly changed and
improved in Visual Studio 2005. You view the Help
topics in a separate window from the VS IDE, so you
can have both windows open at the same time.
1-35
Visual Studio Help Additional Info (2 of 2)
 When you choose
How Do I, Search,
Contents, Index, or
Help Favorites from
the Help menu, a new
window opens on top
of the IDE window.
You can switch from
one window to the
other, or resize the
windows to view both
on the screen if your
screen is large
enough.
1-36