Microsoft VB 2005: Reloaded, Advanced

1
Microsoft VB 2005 Reloaded, Advanced

• Chapter 1
• Reviewing Microsoft Visual Basic 2005 Reloaded
  Part I

2
Objectives

• Design and create a user interface for an
  application
• Use variables and constants in methods to perform
  calculations
• Create pseudocode, flowcharts, and program code
  for the sequence, selection, and repetition
  structures
• Create a project, solution, and application in
  Visual Basic 2005

3
An Introduction to Visual Basic 2005

• Get started using the Visual Studio 2005
  integrated development environment (IDE)

4
Programmers and Programming Languages

• Programmer categories
• Systems programmers
• Write and maintain programs for fundamental
  operating functions
• Application programmers
• Write and maintain programs to handle real-world
  tasks
• Programming languages
• Machine languages
• Assembly languages
• High-level languages

5
Programmers and Programming Languages (continued)
6
Procedure-Oriented and Object-Oriented Programming

• Procedure-oriented programming
• Program code is broken into groups of procedures
• Examples FORTRAN, Pascal, and C
• Object-oriented programming (OOP)
• Gives greater attention to various interacting
  objects
• Use their own internal data and procedures to
  accomplish application objectives
• Examples Visual Basic, Java, and C

7
Procedure-Oriented and Object-Oriented
Programming (continued)

• Object-oriented terminology
• Object
• Instance of a class in computer memory
• Class
• Unit of program code that defines a category of
  objects
• Attributes (also called properties)
• Characteristics that describe an object
• Behaviors (also called procedures or methods)
• Operations that an object is capable of performing

8
Procedure-Oriented and Object-Oriented
Programming (continued)

• Object-oriented terminology (continued)
• Instantiation
• Process of creating an object in computer memory
• Abstraction
• Means using the properties and methods of objects
  
• Without worrying about how they are implemented
• Inheritance
• Process by which a derived class can
  automatically reuse the properties and methods of
  a base class

9
Procedure-Oriented and Object-Oriented
Programming (continued)

• Object-oriented terminology (continued)
• Polymorphism
• Enables one method to have several different
  implementations
• Depending on the type of object calling the method

10
Procedure-Oriented and Object-Oriented
Programming (continued)
11
Visual Studio 2005

• Microsofts IDE for creating an object-oriented
  computer application
• Uses the following languages
• Visual Basic
• Visual C
• Visual C
• Visual J
• Integrated development environment (IDE)
• Tools for creating, compiling, and testing
  programs

12
Visual Studio 2005 (continued)

• User interface
• Enables user to interact with the application
• Visual Studio 2005 application types
• Console application
• Windows-based application
• Web-based application
• Microsoft .NET Framework 2.0
• Development and execution environment
• Allows different programming languages and
  libraries to work together to create applications

13
Visual Studio 2005 (continued)

• The common language runtime (CLR)
• Core runtime engine of Microsoft .NET Framework
• Compiles and executes the IL for a variety of
  computer platforms
• Solutions, projects, and files
• Components of a Visual Studio 2005 application
• Solution contains projects for an application
• Project contains files for a specific part
• Starting Microsoft Visual Studio 2005

14
Visual Studio 2005 (continued)
15
Visual Studio 2005 (continued)
16
Creating a Visual Basic Windows-Based Application
17
Creating a Visual Basic Windows-Based Application
(continued)
18
Managing the Windows in the IDE

• Click View in the menu bar to open windows
• Auto Hide option
• Hides the window but displays a tab for the
  window on the left or right side of the IDE
• Moving the mouse over this tab causes the window
  to temporarily appear
• Undock a window
• By double-clicking its title bar
• Redock by dragging to sides or corners of the IDE

19
The Windows Form Designer Window

• Contains a Windows Form object
• Title bar and the minimize/maximize/close buttons
• Form is used to create a graphical user interface
  (GUI) for the application
• And holds other objects

20
The Solution Explorer Window

• Lists the projects, folders, and files within a
  solution
• Within each project are a My Project node
• Double-clicking the My Project node opens the
  Project Designer window
• Contains a wide variety of project management
  tools
• .vb files
• Visual Basic source files
• Code is written by you or automatically by the
  IDE
• Form1.vb is a form file

21
The Properties Window

• Objects have attributes or properties
• A Visual Basic file is an object
• Its properties are displayed in the Properties
  window
• Properties of a Windows Form object
• Object box contains the name of the object
  followed by System.Windows.Forms.Form
• Namespace is a name given to a collection of
  related classes
• System namespace contains all the basic classes
  for creating Visual Basic applications

22
The Properties Window (continued)

• Properties of a Windows Form object
• Name meaningful name given to the form
• Text text that appears in the forms title bar
• StartPosition where the form will be positioned
  on the screen
• Notes on the notation used
• Hungarian notation (old notation)
• frmMain
• New notation
• MainForm (using Pascal case)

23
The Toolbox Window

• Also called the Toolbox
• Contains tools for building an application
• Controls
• Another name for objects added to a form
• Can be dragged from the Toolbox to the form
• And then manipulated to meet the needs of the
  application
• The Label tool
• Can create a label control on a form
• A label displays text in the form

24
The Toolbox Window (continued)
25
The Toolbox Window (continued)
26
The Toolbox Window (continued)

• Notation
• Control names are written using camel notation
• Examples
• commissionLabel
• calculateButton
• The Button tool
• Creates a button control on a form
• When the user clicks a button on a form, a
  specific action (as defined by the programmer)
  occurs

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The Code Editor Window

• Event example
• Clicking a button in a form
• Event procedure
• Tells the application what to do when an event
  occurs
• Written in the Code Editor window
• Open Code Editor window
• Click View and then Code in the menu

28
The Code Editor Window (continued)
29
The Code Editor Window (continued)

• Creating a Sub procedure for a control
• Sub procedure
• Block of code that performs specific tasks
• Select an object from the Class Name list box
• And an event from the Method Name list box
• Keyword
• Also called a reserved word
• Has a special meaning in a programming language

30
The Code Editor Window (continued)
Procedure handles Click event for exitButton
Procedure header
Object
Event
31
The Code Editor Window (continued)

• The Me.Close method
• Causes a form to close and an application to
  terminate
• Me refers to the specific instance of a class or
  structure in which the code is currently
  executing

32
Debugging an Application

• Startup form
• Form that is automatically displayed when an
  application is started
• Specified using the Solution Explorer window
• Save an application
• Click the Save All button in the Standard toolbar
  or
• Click File on the menu bar and then click Save
  All
• Test an application
• Click Start Debugging button in Standard toolbar
  or
• Press the F5 key on the keyboard

33
Debugging an Application (continued)

• Test an application (continued)
• Saves the application and creates an .exe file
• .exe file is stored in the projects bin folder
• End an application
• Click Stop Debugging button in Standard toolbar
  or
• Click Close button in the applications title bar

34
Printing Your Code

• Steps
• Make the Code Editor window active
• Click the plus boxes only for code you want to
  print
• Click File on the menu bar, click Print, click OK

35
Closing and Opening a Solution

• Close the current solution
• Click File on the menu bar and click Close
• Open a solution
• Click File on the menu bar, then click Open File
• Locate the solution filename (with the .sln
  extension) and double-click it
• Only one solution can be open in a single Visual
  Studio IDE at any one time
• You can open several applications in separate
  Visual Studio IDEs

36
Creating a User Interface

• Explore how to plan an application and design a
  user interface
• Using the Visual Studio 2005 IDE

37
Planning an Application

• Necessary for successful application development
• TOE (Task, Object, Event) chart
• One way of planning a Visual Basic application
• Helps you
• Identify the tasks that the application should
  perform
• Identify the objects to which the tasks will be
  assigned
• Identify the events that will trigger these
  objects to perform the tasks
• After TOE chart is done, you can design the GUI

38
Planning an Application (continued)
39
Identifying the Application Tasks

• Consider the following questions
• What information should be displayed in the
  interface and/or printed to the printer?
• What information will the user need to enter into
  the user interface?
• What information will the application need to
  calculate?
• How will the user end the application?
• Will previous information need to be cleared from
  the screen before new information is entered?

40
Identifying the Objects

• Objects perform tasks
• Form object collects information on the screen
• TextBox objects are used to enter data
• Label objects are used to display data
• Button objects are needed to perform specific
  actions

41
Identifying the Events

• Visual Basic automatically handles data entry for
  text boxes
• As well as data display for text boxes and labels
• You must identify events for the buttons

42
Identifying the Events (continued)
43
Identifying the Events (continued)
44
Designing the User Interface

• You need to design exactly where the controls
  will be located within the form
• Primary window
• Main user interface
• Dialog boxes
• Non-resizable windows that support and supplement
  a users activities in the primary window
• FormBorderStyle property of the Form object
• Controls the appearance and functionality of an
  applications primary window

45
Designing the User Interface (continued)

• Arranging the controls
• Group together related controls using
• GroupBox control
• Creates a border around a group of controls and a
  caption for the group
• Panel control
• Can have scroll bars
• TableLayoutPanel control
• Provides a table structure for controls
• These controls are found in the Containers
  section of the Toolbox

46
Designing the User Interface (continued)
47
Designing the User Interface (continued)

• Aligning and sizing the controls
• Select them
• Click Format in the menu bar
• Choose one of several options in the Format menu
• Including graphics in the user interface
• See Figure 1.13
• Graphics in a user interface should be limited
• Including different fonts in the user interface
• An objects Font property controls the objects
  text type, style, and size

48
Designing the User Interface (continued)
49
Designing the User Interface (continued)

• Including color in the user interface
• Use this feature sparingly
• Limit colors to three that are complementary
• Assigning access keys
• Access key allows an object to be selected using
  a combination of the Alt key with a letter or
  number
• Enter an ampersand () just before the desired
  letter in the controls Text property
• Setting the TabIndex property
• Determines the order in which a control receives
  focus when the Tab key or an access key is used

50
Designing the User Interface (continued)

• Setting the TabIndex property (continued)
• Focus is the ability of an object to accept user
  input
• Change the tab order by selecting a control and
  changing its TabIndex property
• Visual Basic assigns this value as controls are
  added
• Easier way
• Click View in the menu bar, then click Tab Order
• Use mouse to click the controls in the desired
  tab order

51
Designing the User Interface (continued)
52
Defining Default and Cancel Buttons

• Default button
• Always selected when the user presses the Enter
  key
• Created by setting the forms AcceptButton
  property to the name of the button
• Cancel button
• Closes the application
• Created by setting the forms CancelButton
  property to the name of the button

53
Variables, Constants, Methods, and Calculations

• Learn how to
• Work with variables
• Create arithmetic expressions
• Provide application output
• Also study techniques for planning, creating,
  testing, and debugging an application

54
Variables

• Variables
• Simply computer memory locations that can store
  specific types of data and are given special
  names
• Selecting a data type for a variable
• Data type is the kind of data a variable can
  store
• Integer data types Integer, Short, and Long
• Floating-point data types Single and Double
• Other special data types Boolean, Byte, Char,
  Decimal, and String
• Default data type Object

55
Variables (continued)

• Selecting a name for a variable
• Identifiers are variable names
• Names should be very descriptive, indicating the
  variables purpose
• Use camel case for variable names
• Visual Basics syntax (rules of a programming
  language) for variable names
• Must begin with a letter or an underscore
• Only letters, numbers, and the underscore (no
  spaces)
• Must not be a Visual Basic keyword word

56
Declaring a Variable
57
Assigning Data to an Existing Variable

• Assignment statement
• variablename value
• A variable may be assigned a literal constant
• Value does not change while an application is
  running
• Variables must be assigned values of the correct
  data type
• Literal type character
• Can change a numeric literal constants data type
  to match that of a variable

58
Assigning Data to an Existing Variable (continued)

• Using the TryParse method
• Data type in Visual Basic is defined by a class
• Method
• Part of a class that performs a specific task
• TryParse method
• Converts a string of numeric characters into an
  actual numeric value of a particular numeric data
  type
• Using the Convert class
• Converts numbers from one data type to another or
  a string to a number

59
Assigning Data to an Existing Variable (continued)
60
Assigning Data to an Existing Variable (continued)
61
Assigning Data to an Existing Variable (continued)
62
Writing Arithmetic Expressions

• Arithmetic expressions
• Perform calculations in Visual Basic
• Contain arithmetic operators
• Precedence numbers
• Order of operation in an expression
• When operators have the same precedence numbers,
  operators are applied from left to right
• Parentheses override normal operator precedence

63
Writing Arithmetic Expressions (continued)
64
The Scope and Lifetime of a Variable

• Scope of a variable
• Context or boundary within an application where
  the variable is declared and can be used
• Types module, procedure, and block scope
• Lifetime of a variable
• Length of time the variable remains in memory
• Static variable
• Procedure-level variable that retains its value
  even when the procedure in which it is declared
  ends

65
The Scope and Lifetime of a Variable (continued)
66
Named Constants

• Named constant
• Like a variable, is a named memory location
• The value of a named constant cannot be changed
  while the application is running
• Useful for holding constants that are used
  repeatedly throughout an application
• Or that may need to be changed by the programmer
  over a period of time

67
Named Constants (continued)
68
Providing for Application Output

• Assigning a value to the property of a control
• See Figure 1.21
• Using the Focus method
• See Figure 1.22
• Formatting numeric output
• See Figure1.23
• Option Explicit and Option Strict
• Option Explicit On
• Using an undeclared variable will then result in
  an error
• Option Strict On
• Prevents implicit type conversion

69
Providing for Application Output (continued)
70
Providing for Application Output (continued)
71
Providing for Application Output (continued)
72
Coding the Skate-Away Sales Application

• Using pseudocode to plan a procedure
• Pseudocode
• Text that describes a procedure
• Using a flowchart to plan a procedure
• Flowchart
• Uses standard symbols to graphically depict a
  procedure

73
Coding the Skate-Away Sales Application
(continued)
74
Coding the calcButton, clearButton, and
exitButton Controls Click Event Procedures
75
Coding the calcButton, clearButton, and
exitButton Controls Click Event Procedures
(continued)
76
Testing and Debugging the Application

• Debugging
• Locating and correcting errors in a program
• Syntax errors
• Violations of a programming languages syntax
• Visual Basic will find syntax errors for you
• Logic errors
• Result when an application provides incorrect
  output
• Due to mistakes in defining the logic of an
  application

77
Testing and Debugging the Application (continued)
78
Making Decisions in Programs

• Ability of an application to make decisions
• Vital part of program functionality

79
The Selection Structure

• Three basic structures used in programming
• Sequence structure
• Selection structure
• Repetition structure
• Selection structure
• Different sets of instructions are processed
  depending on certain conditions in the program

80
Writing Pseudocode for the If and If/Else
Selection Structures
81
Flowcharting the If and If/Else Selection
Structures
82
Coding the If and If/Else Selection Structures
83
Comparison Operators

• Six comparison operators
• , gt, gt, lt, lt, and ltgt
• Logical expression can contain both arithmetic
  operators and comparison operators
• Arithmetic operators always take precedence over
  comparison operators
• All comparison operators have the same precedence
• Executed left to right unless parentheses are used

84
Using the ToUpper and ToLower Methods
85
Logical Operators

• Logical operators (or Boolean operators)
• Allow you to create compound logical expressions
• Can be used as conditions in If and If / Else
  selection structures
• Operators (in order of precedence)
• Not, And, and AndAlso Or and OrElse and Xor
• Short-circuit evaluation
• When Visual Basic determines logical outcome of a
  compound expression, it ceases to evaluate the
  other parts of the expression

86
Performing Data Validation

• Data validation
• To verify that users are entering valid data
• Extremely important
• Use If or If/Else selection structures
• String.IsNullorEmpty(string)
• Checks if a text box contains data before
  proceeding with processing
• Returns True or False

87
Modifying the Skate-Away Sales Application

• Problem
• User can enter a non-numeric character in either
  the blueTextBox or the yellowTextBox
• Zeros appear for total skateboards and total
  price
• Modify application to display an error message if
  one of these text boxes does not contain an
  integer

88
The MessageBox.Show Method

• Syntax
• MessageBox.Show(text, caption, buttons,
  icon,defaultButton)
• Displays a dialog box that contains a text

89
The MessageBox.Show Method (continued)
90
The MessageBox.Show Method (continued)
91
Nested Selection Structures

• Nested selection structure
• A selection structure, located within an outer
  selection structure
• Allows for multiple decisions by including
  additional selection structures within the true
  or false path

92
Nested Selection Structures (continued)
93
The If/ElseIf/Else Structure

• Facilitates decisions with more than two choices
• Equivalent to multiple nested If/Else structures

94
The Case Selection Structure
95
The Case Selection Structure (continued)
96
Generating Random Numbers

• Pseudo-random number generator
• Produces a sequence of numbers that meet certain
  statistical requirements for randomness

97
Generating Random Numbers (continued)
98
Repeating Program Instructions

• Objectives
• Review how to perform looping
• Work with several different kinds of Visual Basic
  controls related to the repetition structure

99
The Repetition Structure

• Repetition structure (also called a loop)
• Repeats a block of code (called the loop body)
  while a certain condition is true
• Types of repetition structures
• Pretest loop
• Evaluates condition before loop body executes
• Posttest loop
• Evaluates condition after loop body executes once

100
The Repetition Structure (continued)

• Repetition statements
• For...Next
• Do...Loop
• For Each...Next

101
The ForNext Statement
102
The ForNext Statement (continued)
103
The Financial.Pmt Method

• Calculates periodic payment on loan or investment
• Often used with a loop
• Syntax
• Financial.Pmt(Rate, NPer, PV, FV, Due)
• The monthly payment calculator application
• Illustrates the use of a ForNext loop
• Selecting the existing text in a text box
• principalTextBox.SelectAll() selects the contents
  of the text box

104
The Financial.Pmt Method (continued)

• Coding a controls TextChanged Event procedure
• In the Code Editor window, select the
  principalTextBox control
• And the TextChanged method

105
Using a ListBox Control in an Interface

• List box displays a list of choices from which
  the user can select zero, one, or more choices
• ListBox class defines the ListBox control
• ListBox.ObjectCollection class defines the
  collection of items contained in the ListBox
• Properties
• Item
• SelectedItems
• SelectedIndex
• SelectionMode

106
Using a ListBox Control in an Interface
(continued)

• The SelectedItems and SelectedIndex properties
• Each item in a list box has an index starting
  with 0
• SelectedItems equals the selected item name
• SelectedIndex equals the selected item index
• SelectionMode determines how many items can be
  selected at the same time
• The SelectedValueChanged and SelectedIndexChanged
  events
• Occur each time an item is selected in a list box

107
Modifying the Monthly Payment Calculator
Application

• Modify to use a list box that contains the
  possible terms of 2, 3, 4, or 5 years for the loan

108
Modifying the Monthly Payment Calculator
Application (continued)
109
Using a Combo Box in an Interface

• Combo box
• Allows the user to select from a list of choices
• Can contain a text field that allows the user to
  type an entry that is not on the list
• Styles of combo boxes in Visual Basic (controlled
  by the DropDownStyle property)
• Simple
• DropDown
• DropDownList

110
The DoLoop Statement

• Used to code both a pretest loop and a posttest
  loop

111
The DoLoop Statement (continued)
112
The DoLoop Statement (continued)
113
Using Counters and Accumulators

• Counter
• Numeric variable for counting something
• Accumulator
• Numeric variable for accumulating (adding) items
• Counters and accumulators are usually initialized
  by setting their initial values to zero
• Updated by adding values to them for each
  iteration of a loop

114
The InputBox Function

• Function
• Predefined procedure that performs a specific
  task
• And then returns a value after completing the
  task
• InputBox function
• Displays a predefined dialog box that contains a
  message
• Along with an OK button, a Cancel button, and an
  input area in which the user can enter information

115
The InputBox Function (continued)
116
The InputBox Function (continued)
117
The Sales Express Application
118
Summary

• Programming language progression
• Machine languages
• Assembly languages
• High-level languages
• High-level languages types
• Procedure-oriented
• Object-oriented
• The Microsoft .NET Framework 2.0 is a platform on
  which .NET applications are created
• Applications created in Visual Studio are
  composed of solutions, projects, and files

119
Summary (continued)

• Create application GUI in the Windows Form
  Designer window
• Variables and named constants are computer memory
  locations that store data
• Types of statements
• Declaration statement
• Assignment statement
• Variable properties
• Scope
• Lifetime

120
Summary (continued)

• Selection structures
• If
• If/Else
• If/ElseIf/Else
• Case Switch
• Repetition structures
• ForNext
• DoLoop
• For EachNext