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
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

5
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

6
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

7
Procedure-Oriented and Object-Oriented
Programming (continued)
8
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

9
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

10
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

11
Visual Studio 2005 (continued)
12
Visual Studio 2005 (continued)
13
Creating a Visual Basic Windows-Based Application
14
Creating a Visual Basic Windows-Based Application
(continued)
15
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

16
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

17
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

18
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

19
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)

20
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

21
The Toolbox Window (continued)
22
The Toolbox Window (continued)
23
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

24
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

25
The Code Editor Window (continued)
26
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

27
The Code Editor Window (continued)
Procedure handles Click event for exitButton
Procedure header
Object
Event
28
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

29
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

30
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

31
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

32
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

33
Creating a User Interface

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

34
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

35
Planning an Application (continued)
36
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?

37
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

38
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

39
Identifying the Events (continued)
40
Identifying the Events (continued)
41
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

42
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

43
Designing the User Interface (continued)
44
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

45
Designing the User Interface (continued)
46
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

47
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

48
Designing the User Interface (continued)
49
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

50
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

51
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

52
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

53
Declaring a Variable
54
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

55
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

56
Assigning Data to an Existing Variable (continued)
57
Assigning Data to an Existing Variable (continued)
58
Assigning Data to an Existing Variable (continued)
59
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

60
Writing Arithmetic Expressions (continued)
61
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

62
The Scope and Lifetime of a Variable (continued)
63
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

64
Named Constants (continued)
65
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

66
Providing for Application Output (continued)
67
Providing for Application Output (continued)
68
Providing for Application Output (continued)
69
Making Decisions in Programs

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

70
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

71
Coding the If and If/Else Selection Structures
72
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

73
Using the ToUpper and ToLower Methods
74
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

75
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

76
The MessageBox.Show Method

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

77
The MessageBox.Show Method (continued)
78
The MessageBox.Show Method (continued)
79
The If/ElseIf/Else Structure

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

80
The Case Selection Structure
81
The Case Selection Structure (continued)
82
Generating Random Numbers

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

83
Generating Random Numbers (continued)
84
Repeating Program Instructions

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

85
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

86
The Repetition Structure (continued)

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

87
The ForNext Statement
88
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

89
The Financial.Pmt Method (continued)

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

90
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

91
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

92
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

93
Modifying the Monthly Payment Calculator
Application (continued)
94
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

95
The DoLoop Statement

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

96
The DoLoop Statement (continued)
97
The DoLoop Statement (continued)
98
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

99
The InputBox Function (continued)
100
The InputBox Function (continued)
101
The Sales Express Application
102
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

103
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

104
Summary (continued)

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