Teaching an Introductory Programming Class Using Visual Basic.NET

Teaching an Introductory Programming Class

Using Visual Basic .NET

Spring 2002 Slide 2

We are...Anita C. MillspaughProfessor, Computer Information SystemsMt. San Antonio college

Julia Case BradleyProfessor Emeritus, Computer Information SystemsMt. San Antonio College

Bradley/Millspaugh texts:VB 4, VB 5, VB 6, Advanced VB, Javaand the new VB .NET

Slide 3Spring 2002

You…

Teach Visual Basic 6?

Are planning to teach Visual Basic .NET?

Have taught an OOP language

such as Java, SmallTalk, or C++?

Spring 2002 Slide 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

Spring 2002 Slide 5

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.

Our Approach

Spring 2002 Slide 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# …

Spring 2002 Slide 7

A new mind set

New keywords:InheritsOverridesOverloads

Terminology introduced in Chapter 1

Concepts covered in Chapter 6

The Biggest Change in VB .NET — OOP

Spring 2002 Slide 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

Spring 2002 Slide 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)

Spring 2002 Slide 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


Chapter 1 — Changes New IDE


Chapter 1 (continued)

TerminologyVS IDESolution ExplorerForm DesignerEditor window

Tabbed display is the default for the IDE

AutoHide toolbox; can be “pinned” open



PushPin

Locked Control

TabbedWindow



A solution can contain multiple projects

Forms, classes, and code modules have a .vb extension

The IDE automatically creates a folder for the project


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



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




CollapsedRegion

CollapsedProcedure

ClassList

Method ListTabs



Complications:

Changing the name of the form requires the project’s 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



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()


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)


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 form’s StartPosition property; no more Form Layout Window


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)

It’s event is CheckChanged

Great new method for setting tab order


Chapter 2 (continued)View / Tab Order


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 methodtxtName.Clear()txtName.Text = “”

Focus method replaces SetFocus

txtName.Focus()



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



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



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)


Chapter 3 (continued) Initialize a variable at declaration

Dim intMax As Integer = 100IDim decRate As Decimal = 0.08D

Declare multiple variables at onceDim 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


Chapter 3 (continued) New assignment Operators += –= *= /= &=

decTotal += decSale

Structured Exception HandlingTry

(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!



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)



MessageBox Icons and buttons

Enumeration of constants


Chapter 4 — Decisions and Conditions Topics Covered

Conditions / Relational Operators

Block Ifs

Compound Conditions

Validation

Message Boxes that return the user response

Debugging



Block IF unchanged

Conditions — always compare like data types

If CInt(txtInput.Text) > 10I Then

String ToUpper and ToLower methods (replace UCase and LCase functions)

If txtInput.Text.ToUpper = “YES”


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 ThenMessageBox.Show("You said Yes!")

ElseMessageBox.Show("You said No!")

End If


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”


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 argumentsPrivate 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)


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


Chapter 5 — Menus, Sub Procedures, and

Sub Functions Topics Covered

Creating Menus and Menu Items

Creating ContextMenus

Displaying Common Dialog Boxes

Writing General Procedures


Chapter 5 — Changes Create a menu by adding a MainMenu control to the

component tray

Great new Menu Designer replaces the Menu Editor



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



New ColorDialog and FontDialog controls

Added to the component tray

Use the control’s Show method to display

Can set and retrieve properties of the control

With dlgColor.Color = frmMain.BackColor

.ShowDialog().frmMain.BackColor = .Color

End With



The FontDialog control 'Change the font for the total label

With dlgFont.Font = lblTotal.Font.ShowDialog()lblTotal.Font = .Font

End With


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 + intNum2End Function


Chapter 6 — OOP Topics Covered

Object-oriented terminology

Multitier applications

Class vs. Object

Visibility — Public, Private, Protected

Constructors

Instantiation

Inheritance


Chapter 6 — Changes Namespaces

Organize class libraries Provide unique naming region Can create your own namespace

Specifying namespaceslblMessage.Font = New System.Drawing.Font( _

"Arial", 12) or

Imports System.Drawing.Font...lblMessage.Font = New Font("Arial", 12)



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


Chapter 6 (continued) Inheritance

New class based on existing class


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– OverridablePublic Class StudentBookSale

Inherits BookSale


Chapter 6 (continued) Inheritance (continued)

In base class

Public Overridable Function _ ExtendedPrice() As Decimal

In derived class

Overrides Function ExtendedPrice() _

As Decimal


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)


Chapter 6 (continued) New Format for Property Procedures

Private mstrLastName As String

Public Property LastName As StringGet LastName = mstrLastName

End GetSet (ByVal Value As String)mstrLastName = Value

End SetEnd Property



ReadOnly and WriteOnly keywords for properties

Private mdecTotalPay As Decimal

ReadOnly Property SalesTotal() As DecimalGet

TotalPay = mdecTotalPayEnd Get

End Property



Shared members — one variable forfor 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


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))



Visibility Private Public Protected

– Accessible only inside the class or a derived class

Garbage Collection is automatic Don’t set objects to Nothing in code


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



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


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.SelectedIndex)

cboCoffee.Items.Remove(cboCoffee.Text)


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


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 control’s PrintPage event procedure

The control fires the event once for each page to print

The program responds in the PrintPage event procedure


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 processprtDocument.Print()

End Sub


Chapter 7 (continued) Set up print page in the control’s PrintPage event:

Private Sub prtDocument_PrintPage( _ByVal sender As Object, ByVal e As _System.Drawing.Printing.PrintPageEventArgs)_Handles prtDocument.PrintPage

'Set up actual output to print

End Sub


Chapter 7 (continued) Use the DrawString method in the control’s 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)


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

PrintPreviewDialog’s Document property The same PrintPage event procedure is used to set

up the print output

ppdPrintPreview.Document = prtDocument

ppdPrintPreview.ShowDialog()



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


Chapter 8 — Arrays Topics Covered

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



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.CheckedChanged, _radYellow.CheckedChanged


Chapter 8 (continued) In shared event procedure:

'Save the name of the selected buttonDim radSelected As RadioButtonradSelected = CType(sender, RadioButton)Select Case radSelected.Name

Case "radBlue"mcolorNew = Color.Blue

Case "radBlack"mcolorNew = Color.Black

Case "radRed"'… rest of code

End Select



All arrays are zero based No Dim Array(LowerBound To UpperBound)

Declare upper subscript unlessinitializing values at declaration

Dim mstrProduct(99) As String

Dim mintValue() As Integer _= {1, 5, 12, 18, 20}



Structures replace User-defined Types

Public Structure ProductDim strDescription As StringDim strID As StringDim intQuantity As IntegerDim decPrice As Decimal

End Structure


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


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


Chapter 9 (continued) A Web project is created in Inetpub\wwwroot


Chapter 9 (continued) Validator Controls run on the client side, eliminating

traffic to the server



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


Chapter 10 — Database Topics Covered

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



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



Specific file OleDbConnection object

Handles data transfer and provides data for dataset. Uses SQL to specify data to retrieve or update.

Actual data. Can contain multiple tables and relationships.

Data displays on the form in bound controls


Chapter 10 (continued) Use the Server Explorer

Manage connections View table structure Drag tables and/or fields

to the form to set up connection and data adapter


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



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


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 dataset’s Update method The automatically-generated SQL statements execute

for any changed rows

– Insert, Delete, Update


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



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()



StreamReaderImports System.IO

Dim datPhone As StreamReader

datPhone = New StreamReader(strFilePath)

If datPhone.Peek <> -1 Then

lblName.Text = datPhone.ReadLine()

lblPhone.Text = datPhone.ReadLine()

End If

datPhone.Close()


Chapter 11 (continued) OpenFileDialog

Display common dialog Allow user to browse for file

Dim dgrResult As DialogResult

dlgOpen.InitialDirectory = Application.StartupPathdgrResult = dlgOpen.ShowDialog() If dgrResult <> DialogResult.Cancel Then

'User didn't click the Cancel buttondatPhone = New StreamReader(dlgOpen.FileName)btnNext.Enabled = TruebtnNext_Click(sender, e)

End If


Chapter 11 (continued) Serialization

Save an object to a file The object’s 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()


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


Chapter 12 — Graphics Topics Covered

Draw shapes, lines, and filled shapes Instantiate Brush and Pen objects Simple animation Timer component Scroll bars Creating pie charts


Chapter 12 — All New

Graphics use GDI+ for greater device independence Based on System.Drawing namespace Graphics object may be on a form or a control Pens draw lines; Brushes draw filled shapes Measurement for graphics is pixels

The Scale function is gone



Create graphics in the form’s Paint event procedure Declare a Graphics object using the PaintEventArgs

Private Sub frmDraw_Paint(ByVal sender As Object, _ ByVal e As System.Windows.Forms.PaintEventArgs) _

Handles MyBase.Paint

'Create a graphics objectDim gr As Graphics = e.Graphics


Chapter 12 (continued) Use a Pen to draw a line or outlined shape Use a Brush for a filled shape

Dim gr As Graphics = e.GraphicsDim penRed As New Pen(Color.Red)Dim brushBlue As New SolidBrush(Color.Blue)

'Draw a red rectanglegr.DrawRectangle(penRed, 10, 10, 30, 30)

'Draw a blue filled circlegr.FillEllipse(brushBlue, 100, 100, 50, 50)



The SetBounds method replaces Move

SetBounds(intX, intY, intWidth, intHeight)

picPlane.SetBounds(intX, intY, _planeWidth, planeHeight)



PictureBox controls hold many more graphic formats Can display an animated GIF file

Timer component appears in the component tray Enabled = False by default — must set to True The Tick event fires when the Interval occurs

Scroll bar changes ValueChanged replaces Change event Minimum property replaces Min Maximum property replaces Max


Chapter 13 — Additional Topics Topics Covered

Multiple Document Interfaces (MDI) Windows Common Controls

Image Lists Toolbars Status bars Calendar

Crystal Reports



An MDI program can have Multiple parent forms Multiple child forms Forms that operate independently

You no longer have to use a different form type as a parent Set parent’s IsMdiContainer property to True For child form, set MdiParent property in code

Dim frmChildOne As New frmChild()

frmChildOne.MdiParent = Me


Chapter 13 (continued) To create a Window menu, set a menu’s MdiList

property to True The Arrange methods are replaced with Layout

methods

Me.LayoutMdi(MdiLayout.TileHorizontal)

Me.LayoutMdi(MdiLayout.TileVertical)

Me.LayoutMdi(MdiLayout.Cascade)



New controls added to the chapter Image list status bar toolbar

Image List You can add and remove images after attaching

the list to a toolbar New collection editor makes adding and removing

images easier



Toolbar Single ButtonClick event for all buttons on toolbar EventArgs argument holds index of clicked button

Select Case tlbParent.Buttons.IndexOf(e.Button)Case 0

mnuDisplayChildOne_Click(sender, e)Case 1

mnuDisplayChildTwo_Click(sender, e)End Select



Crystal Reports are back and are more powerful No code is required to write a report You design a template and add a

CrystalReportViewer object to the form


Questions ???


Thank You

We appreciate your being here with us.

Have fun. It’s a great product and should be fun to teach!!!

Documents

Teaching an Introductory Programming Class Using Visual Basic.NET