Teaching%20an%20Introductory%20Programming%20Class

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Teaching%20an%20Introductory%20Programming%20Class

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Title: Teaching%20an%20Introductory%20Programming%20Class

1
Teaching an Introductory Programming Class

Using Visual Basic .NET

2
We are...
Anita C. Millspaugh Professor, Computer
Information Systems Mt. San Antonio
college Julia Case Bradley Professor Emeritus,
Computer Information Systems Mt. San Antonio
College Bradley/Millspaugh texts VB 4, VB 5,
VB 6, Advanced VB, Java and the new VB .NET
3
You
Teach Visual Basic 6? Are planning to teach
Visual Basic .NET? Have taught an OOP language
such as Java, SmallTalk, or C?
4
Our Goals for Today

Help you transition from VB 6 to VB .NET
Look at the differences between
Visual Basic 6 object based event driven
Visual Basic .NET object oriented
Introduce the new Visual Studio IDE
(integrated development environment)
Show the changes to the language and the new
features

5
Our Approach

This is an introductory programming course
Main topics
Program planning
Programming logic
Variables, constants, calculations, decisions,
loops, data files
Language syntax
Coding standards
Testing and debugging
The VB .NET course still covers these topics,
with OOP concepts embedded throughout.

6
What is the .NET Framework?

Platform for building and running applications
Designed for cross-platform compatibility
Common Language Runtime (CLR)
Share methods and objects from different
languages
Many languages to choose from VB, C,
COBOL, Fortran, J

7
The Biggest Change in VB .NET OOP

A new mind set
New keywords
Inherits
Overrides
Overloads
Terminology introduced in Chapter 1
Concepts covered in Chapter 6

8
The Second Biggest Change Web Forms

Programming for the Web vs. Windows
New set of controls
Client side vs. server side
Web page layout
Very simple projects presented in Chapter 9

9
The Third Biggest Change Data File Handling

Database uses ADO .NET (Chapter 10)
No Data control
Simple program is more difficult
Binding is more robust and likely to be used by
real programmers
Must write code for navigation
Simple data files use streams (Chapter 11)

10
Chapter 1 IntroductionTopics Covered

Objects, Methods, and Properties
The Visual Studio IDE
Planning a Project
Creating a Project
Labels and Buttons
Code
Syntax and Logic Errors
Help

11
Chapter 1 Changes

New IDE

12
Chapter 1 (continued)

Terminology VS IDE Solution
Explorer Form Designer Editor window
Tabbed display is the default for the IDE
AutoHide toolbox can be pinned open

13
Chapter 1 (continued)
PushPin
Tabbed Window
Locked Control
14
Chapter 1 (continued)

A solution can contain multiple projects
Forms, classes, and code modules have a .vb
extension
The IDE automatically creates a folder for the
project

15
Chapter 1 (continued)

Form Designer
Similar to VB 6
Double-Click a control in the toolbox
New default-sized control
Appears on top of a selected control
Top-left of the form if no control is selected
Locked controls have a dark border when
selected
Command Buttons are now Buttons
Use btn for prefix
No more Caption property now it is Text

16
Chapter 1 (continued)

The Editor window (formerly the Code window)
Lots more IntelliSense help can be confusing
Declarations section replaces General
Declarations
Class List and Method List
- Selecting the object and event is somewhat
different
Collapsible Regions in code

17
Chapter 1 (continued)
Tabs
Method List
Class List
Collapsed Region
Collapsed Procedure
18
Chapter 1 (continued)

Complications
Changing the name of the form requires the
projects startup object to be changed
PrintForm is no longer supported
IDE Print does not offer Form Image or Form
Text
No edit-and-continue execution
Must restart (recompile) if edits are made
during break time

19
Chapter 1 (continued)

Form and controls no longer have Caption property
Forms, buttons, labels all use the Text property
The Alignment property becomes TextAlign
The maximum length of identifiers is 16,383
All new Help MSDN
Redesigned Object Browser
Me.Close()

20
Chapter 2 More Controls Topics Covered

Check Boxes
Radio Buttons
Group Boxes
Picture Boxes
Designing an Interface
Setting the Tab Order
Setting up keyboard access keys (shortcuts)

21
Chapter 2 Changes

No more Image control, Line control, or Shape
control
Use PictureBox for graphics Label for lines
OptionButton becomes RadioButton
Frame becomes GroupBox
AcceptButton and CancelButton are properties of
the form
Set the forms StartPosition property no more
Form Layout Window

22
Chapter 2 (continued)

PictureBox controls
Use Image property to hold a graphic
Set SizeMode property to StretchImage
replaces Stretch property of Images
CheckBox controls
Value property becomes the Checked property
(Boolean)
Its event is CheckChanged
Great new method for setting tab order

23
Chapter 2 (continued)
View / Tab Order
24
Chapter 2 (continued)

New component tray holds non-visible controls
To add ToolTips, add a ToolTip control to the
component tray
New ToolTip on ToolTip1 property is added to the
form and all controls
Text boxes have a Clear method
txtName.Clear()
txtName.Text
Focus method replaces SetFocus
txtName.Focus()

25
Chapter 2 (continued)

Many colors available through the Color class
lblMessage.ForeColor Color.Blue
Color.Red
Color.Yellow
Color.Aquamarine
Color.Bisque
Color.Chocolate
Color.Cadetblue
and dozens more

26
Chapter 3 Variables,Constants and
Calculations Topics Covered

Variables, constants, calculations
Data types
Converting text input to numeric
Formatting output
Error Handling (Exceptions)
Message Boxes

27
Chapter 3 Changes

Strongly Typed Data
Option Strict On
Enforces strong data typing
Data Types
Short (old Integer)
Integer (old Long)
Decimal (Currency is gone)
Object ( Variant is gone)
Date (replaces DateTime)

28
Chapter 3 (continued)

Initialize a variable at declaration Dim
intMax As Integer 100I
Dim decRate As Decimal 0.08D
Declare multiple variables at once Dim
intCount, intNumber As Integer
Convert all input to correct data type (Do not
use Val function)
decSale CDec(txtSale.Text)
CDec and CInt Can parse , () -
CInt rounds to nearest EVEN number

29
Chapter 3 (continued)

New assignment Operators /
decTotal decSale
Structured Exception Handling
Try
(Code that could cause an exception)
Catch excName As excType
(Code to handle the exception)
Finally
(Code to execute in any case)
End Try
We can catch input errors before covering If
statements!

30
Chapter 3 (continued)

MessageBox class
MessageBox.Show(Arguments)
Several choices for argument list
Introduces concept of Overloaded functions
Multiple signatures to choose from
MessageBox.Show(TextMessage)
MessageBox.Show(TextMessage, TitlebarText)
MessageBox.Show(TextMessage, TitlebarText,
_ MessageBoxButtons)
MessageBox.Show(TextMessage, TitlebarText,
_ MessageBoxButtons, MessageBoxIcon)

31
Chapter 3 (continued)

MessageBox Icons and buttons
Enumeration of constants

32
Chapter 4 Decisions and Conditions Topics
Covered

Conditions / Relational Operators
Block Ifs
Compound Conditions
Validation
Message Boxes that return the user response
Debugging

33
Chapter 4 Changes

Block IF unchanged
Conditions always compare like data types
If CInt(txtInput.Text) gt 10I Then
String ToUpper and ToLower methods
(replace UCase and LCase functions)
If txtInput.Text.ToUpper YES

34
Chapter 4 (continued)

MessageBox.Show method returns an object of
type DialogResult
Dim dgrResponse As DialogResult
dgrResponse MessageBox.Show(Shall we?", _
"The Question", MessageBoxButtons.YesNo, _
MessageBoxIcon.Question)
If dgrResponse DialogResult.Yes Then
MessageBox.Show("You said Yes!")
Else
MessageBox.Show("You said No!")
End If

35
Chapter 4 (continued)

Replace vbCrLf, vbCr, vbLf with constants in the
ControlChars class
ControlChars.NewLine
Dim strMultilineMessage As String
strMultilineMessage Line 1 _
ControlChars.NewLine Line 2

36
Chapter 4 (continued)

Calling a procedure requires parentheses
VB 6 Way
ClearControls
or Call ClearControls()
VB .NET Way
Call ClearControls()
Calling an event procedure requires two arguments
Private Sub btnExit_Click(ByVal sender _ As
System.Object, ByVal e _ As System.EventArgs)
Handles btnExit.Click
Call the event procedure
Call btnExit_Click(sender, e)

37
Chapter 4 (continued)

Debug.WriteLine
(Replaces Debug.Print)
Debug.WriteLine(I got this far)
Clear the Output Window
Right-click / Clear All
New Autos window shows current value of
variables and objects within approx. 6 statements
Immediate window only valid at run time
Keyboard shortcut for Step Into F11

38
Chapter 5 Menus, Sub Procedures, and Sub
Functions Topics Covered

Creating Menus and Menu Items
Creating ContextMenus
Displaying Common Dialog Boxes
Writing General Procedures

39
Chapter 5 Changes

Create a menu by adding a MainMenu control to the
component tray
Great new Menu Designer replaces the Menu Editor

40
Chapter 5 (continued)

For Context menus, add a ContextMenu control
A ContextMenu uses the same Menu Designer as a
MainMenu
Attach a context menu by setting the ContextMenu
property of a control or the form

41
Chapter 5 (continued)

New ColorDialog and FontDialog controls
Added to the component tray
Use the controls Show method to display
Can set and retrieve properties of the control
With dlgColor
.Color frmMain.BackColor
.ShowDialog()
.frmMain.BackColor .Color
End With

42
Chapter 5 (continued)

The FontDialog control
'Change the font for the total label
With dlgFont
.Font lblTotal.Font
.ShowDialog()
lblTotal.Font .Font
End With

43
Chapter 5 (continued)

Arguments are passed ByVal (by default)
The Editor adds ByVal if you leave it out
New Return statement
Can still set function name to value
Better to use the Return statement
Private Function CalculateSum( _
ByVal intNum1 As Integer, _
ByVal intNum2 As Integer) As Integer
'Calculate the sum of the numbers
Return intNum1 intNum2
End Function

44
Chapter 6 OOP Topics Covered

Object-oriented terminology
Multitier applications
Class vs. Object
Visibility Public, Private, Protected
Constructors
Instantiation
Inheritance

45
Chapter 6 Changes

Namespaces
Organize class libraries
Provide unique naming region
Can create your own namespace
Specifying namespaces
lblMessage.Font New System.Drawing.Font( _
"Arial", 12)
or
Imports System.Drawing.Font
...
lblMessage.Font New Font("Arial", 12)

46
Chapter 6 (continued)

Classes vs. Objects
Use New keyword to instantiate
For exception handling, declare the name at the
module level and instantiate in a Try/Catch block
Encapsulation
Classes hide implementation details
Only the Public properties and methods can be
seen by other classes

47
Chapter 6 (continued)

Inheritance
New class based on existing class

48
Chapter 6 (continued)

Inheritance (continued)
All public properties and methods are inherited
Visual inheritance can inherit a form
New keywords to support inheritance
Inherits
Overrides
Overridable
Public Class StudentBookSale
Inherits BookSale

49
Chapter 6 (continued)

Inheritance (continued)
In base class
Public Overridable Function _
ExtendedPrice() As Decimal
In derived class
Overrides Function ExtendedPrice() _ As
Decimal

50
Chapter 6 (continued)

Polymorphism
Consistent naming, so that many classes can have
the identically-named methods that perform an
action appropriate for the object
Example The Add method for collections, lists,
arrays, database
Identically named methods in a class, with
different implementations based on the arguments
Keyword Overloads
Example MessageBox.Show method, which has many
different argument lists (signatures)

51
Chapter 6 (continued)

New Format for Property Procedures
Private mstrLastName As String
Public Property LastName As String
Get
LastName mstrLastName
End Get
Set (ByVal Value As String)
mstrLastName Value
End Set
End Property

52
Chapter 6 (continued)

ReadOnly and WriteOnly keywords for properties
Private mdecTotalPay As Decimal
ReadOnly Property SalesTotal() As Decimal
Get
TotalPay mdecTotalPay
End Get
End Property

53
Chapter 6 (continued)

Shared members one variable for for all
instances of the class
Often used for totals and counts
'SalesTotal property
Private Shared mdecSalesTotal As Decimal
'SalesCount property
Private Shared mintSalesCount As Integer

54
Chapter 6 (continued)

Constructors New() method
Replaces ClassInitialize procedure
Constructors are not inherited
Must write your own New() procedure
First statement should be
MyBase.New()
Constructors can be overloaded
Parameterized Constructors
mBookSale New BookSale(txtTitle.Text, _
CInt(txtQuantity.Text), _
CDec(txtPrice.Text))

55
Chapter 6 (continued)

Visibility
Private
Public
Protected
Accessible only inside the class or a derived
class
Garbage Collection is automatic
Dont set objects to Nothing in code

56
Chapter 7 Lists, Loops, and Printing Topics
Covered

List Boxes and Combo Boxes
Items Collection
Methods and Properties of Lists
Do Loops
For/Next Loops
Printing and Print Preview

57
Chapter 7 Changes

The DropDownStyle property of ComboBoxes replaces
the Style property
No List property or ItemData property
Lists have an Items collection
Items.Add(value)
Items.Insert(position)
Items.Remove(text string)
Items.RemoveAt(index)
Items.Clear()
Items.Count
SelectedIndex property of control

58
Chapter 7 (continued)

lstSchools.Items.Add("Harvard")
cboMajors.Items.Insert(1, cboMajors.Text)
intTotalItems lstItem.Items.Count
strSelectedFlavor _ lstFlavor.Items(lstFlavor
.SelectedIndex)
cboCoffee.Items.RemoveAt( _ cboCoffee.SelectedInd
ex)
cboCoffee.Items.Remove(cboCoffee.Text)

59
Chapter 7 (continued)

New events
SelectedIndexChanged
Event to use when the user makes a selection
Click event no longer supported for lists
TextChanged
One event for each keystroke
Enter and Leave replace GotFocus and LostFocus
events
FindString and FindStringExact methods
Not covered in this text
SelectAll method
For text boxes or text portion of a combo box

60
Chapter 7 (continued)

Printing is completely changed
No more Printer.Print, Form.Print,
PictureBox.Print
All text printing is performed with a DrawString
method on a Graphics object
Add a PrintDocument control to the component tray
Write all printing logic in the controls
PrintPage event procedure
The control fires the event once for each page to
print
The program responds in the PrintPage event
procedure

61
Chapter 7 (continued)

Begin a printing operation
Private Sub btnPrint_Click(ByVal _ sender As
System.Object, ByVal _
e As System.EventArgs) _
Handles btnPrint.Click
'Print output on the printer
'Start the print process
prtDocument.Print()
End Sub

62
Chapter 7 (continued)

Set up print page in the controls PrintPage
event
Private Sub prtDocument_PrintPage( _ByVal sender
As Object, ByVal e As _System.Drawing.Printing.Pr
intPageEventArgs)_Handles prtDocument.PrintPage
'Set up actual output to print
End Sub

63
Chapter 7 (continued)

Use the DrawString method in the controls
PrintPage event
'Declarations at the top of the procedure
Dim fntPrintFont As New Font("Arial", 12)
'More declarations here
'Print a line
e.Graphics.DrawString(strPrintLine, _
fntPrintFont, Brushes.Black, _
sngPrintX, sngPrintY)

64
Chapter 7 (continued)

Graphics objects
Must define fonts and brushes to create text
Set up print lines with the DrawString method
Print Preview
Add a PrintPreviewDialog control to the form
Assign the PrintDocument control to the
PrintPreviewDialogs Document property
The same PrintPage event procedure is used to set
up the print output
ppdPrintPreview.Document prtDocument
ppdPrintPreview.ShowDialog()

65
Chapter 7 (continued)

The Good News
Do Loops and For / Next Loops are unchanged

66
Chapter 8 Arrays Topics Covered

Select Case structure
Shared events
Arrays
Structures
Table lookup
Combining list controls and arrays
Multi-dimensional arrays

67
Chapter 8 Changes

Shared events (no control arrays)
Private Sub radBlue_CheckedChanged( _ ByVal
sender As System.Object, _
ByVal e As System.EventArgs) _
Handles radBlue.CheckedChanged,
radBlack.CheckedChanged, _
radRed.CheckedChanged, _ radWhite.CheckedChang
ed, _
radYellow.CheckedChanged

68
Chapter 8 (continued)

In shared event procedure
'Save the name of the selected button
Dim radSelected As RadioButton
radSelected CType(sender, RadioButton)
Select Case radSelected.Name
Case "radBlue"
mcolorNew Color.Blue
Case "radBlack"
mcolorNew Color.Black
Case "radRed"
' rest of code
End Select

69
Chapter 8 (continued)

All arrays are zero based
No Dim Array(LowerBound To UpperBound)
Declare upper subscript unless initializing
values at declaration
Dim mstrProduct(99) As String
Dim mintValue() As Integer _ 1, 5, 12, 18,
20

70
Chapter 8 (continued)

Structures replace User-defined Types
Public Structure Product
Dim strDescription As String
Dim strID As String
Dim intQuantity As Integer
Dim decPrice As Decimal
End Structure

71
Chapter 9 Web Forms Topics Covered

Client vs. Server
Running Web Forms in a browser
Web controls
Event structure of Web programs
Layouts
Validator Controls

72
Chapter 9 All New

Must install IIS before installing VS .NET
Properties, methods, and events are different
from Windows Forms
Examples
Name property is ID
Form_Load is Page_Load
Web Controls differ from Windows controls even
when they have the same name

73
Chapter 9 (continued)

A Web project is created in Inetpub\wwwroot

74
Chapter 9 (continued)

Validator Controls run on the client side,
eliminating traffic to the server

75
Chapter 9 (continued)

Web projects are not easy to transfer from one
computer or folder to another location

76
Chapter 10 Database Topics Covered

ADO.NET
XML
Datasets in Windows and Web projects
Record navigation
Parameterized queries
Updating a dataset

77
Chapter 10 Changes

No Data control
Disconnected datasets with an adapter
Two adapters available
SQL Server
OleDb (Works well with Access files)
Must write navigation code
Data is transferred in XML code
Generated automatically

78
Chapter 10 (continued)
OleDbConnection object
Actual data. Can contain multiple tables and
relationships.
Data displays on the form in bound controls
Specific file
Handles data transfer and provides data for
dataset. Uses SQL to specify data to retrieve or
update.
79
Chapter 10 (continued)

Use the Server Explorer
Manage connections
View table structure
Drag tables and/or fieldsto the form to set up
connection and data adapter

80
Chapter 10 (continued)

A Configure Data Adapter wizard steps through
creating the dataset
The dataset can be based on an SQL Select
statement or a stored procedure
The wizard presents a Query Builder for building
SQL Select statements
Similar to the Query Designer in Access
Creates the Select statement
Can also generate the Insert, Delete, and Update
SQL statements for updating the dataset
You can preview the data from the file

81
Chapter 10 (continued)

Bind the data to individual controls with the
DataBindings properties
At Form_Load or Page_Load call the Fill method to
generate the dataset
DataAdapterName.Fill(DataSetName)
Dataset is disconnected
Windows Forms Bound controls are filled
automatically
Web Forms Must execute the BindData method
Bound controls are filled when BindData executes
Web Forms are static Only current record is
transferred

82
Chapter 10 (continued)

All new Datagrid controls
One for Windows forms another for Web forms
Navigation requires code
No MoveNext, MovePrevious methods
Me.BindingContext(DsBooks1, Books).Position
1
Microsoft recommends one dataset per table
Save changes back to the original data source by
executing the datasets Update method
The automatically-generated SQL statements
execute for any changed rows
Insert, Delete, Update

83
Chapter 11 Data Files Topics Covered

Use streams to store and retrieve data
Save and restore values in a list
Use serialization to save the values of an object

84
Chapter 11 Changes

Data file handling is completely new
Streams transfer data
StreamReader
StreamWriter
Imports System.IO
Dim datPhone As StreamWriter
datPhone New StreamWriter(strFilePath)
datPhone.WriteLine(txtName.Text)
datPhone.WriteLine(txtPhone.Text)
datPhone.Close()

85
Chapter 11 (continued)

StreamReader
Imports System.IO
Dim datPhone As StreamReader
datPhone New StreamReader(strFilePath)
If datPhone.Peek ltgt -1 Then
lblName.Text datPhone.ReadLine()
lblPhone.Text datPhone.ReadLine()
End If
datPhone.Close()

86
Chapter 11 (continued)

OpenFileDialog
Display common dialog
Allow user to browse for file
Dim dgrResult As DialogResult
dlgOpen.InitialDirectory Application.StartupPath
dgrResult dlgOpen.ShowDialog()
If dgrResult ltgt DialogResult.Cancel Then 'User
didn't click the Cancel button
datPhone New StreamReader(dlgOpen.FileName) btn
Next.Enabled True
btnNext_Click(sender, e)
End If

87
Chapter 11 (continued)

Serialization
Save an object to a file
The objects class must be declared as
serializable
In the program that creates the object
Dim datBooks As FileStream _
New FileStream("Books", FileMode.Create)
Dim BookFormatter As BinaryFormatter _
New BinaryFormatter()
BookFormatter.Serialize(datBooks, mBookSale)
datBooks.Close()

88
Chapter 11 (continued)

Deserialization Restore an object from a file
Create a FileStream object in the Open mode
Declare a Formatter object
Use the Formatter's Deserialize method,
converting the input to the desired object type
Transfer the fields from the object to the screen
Close the stream
FileStream object has Create and Open modes

89
Chapter 12 Graphics Topics Covered