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Microsoft VB 2005: Reloaded, Advanced

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Title: 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
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