1. VB.Net Introduction

2. Visual Studio .NET 2005 It supports VB.Net, J#, C#, and C++. Demo:
Start page: Recent projects
Starting project:
File/New Project/Project types: Windows Application
View:
Solution Explorer/Data Sources
Server Explorer
Property Window
ToolBox
Form design view/Form code view
Tools/Option
Environment
Projects and Solutions
VB defaults
Project/Add New Item
Project properties: Right-click project name and choose Properties
Start Up form
Property window example

3. Introduction to Visual Basic .Net
Event-driven programming
The interface for a VB program consists of one or more forms, containing one or more controls (screen objects).
Form and controls have events that can respond to. Typical events include clicking a mouse button, type a character on the keyboard, changing a value, etc.
Event procedure

4. Form Properties: Events:
Name, FormBorderStyle, Text, BackColor, BackImage, Opacity
Events:
Load, FormClosing, FormClosed
GotFocus, LostFocus
MouseHover, Click, DoubleCLick

5. Typical VB.Net Controls
TextBox
Label
Button
CheckBox
RadioButton
ListBox
ComboBox
PictureBox

6. Text Box
Properties:
AutoSize, BorderStyle, CauseValidation, Enabled, Locked, Multiline, PasswordChar, ReadOnly, ScrollBar, TabIndex, Text, Visible, WordWrap, etc.
Properties can be set at the design time or at the run time using code.
To refer to a property:
ControlName.PropertyName
Ex. TextBox1.Text
Note: The Text property is a string data type and automatically inherits the properties and methods of the string data type.

7. Typical VB.Net Programming Tasks
Creating the GUI elements that make up the application’s user interface.
Visualize the application.
Make a list of the controls needed.
Setting the properties of the GUI elements
Writing procedures that respond to events and perform other operations.

8. Demo Num1 Num2 Sum = .Control properties
.Event: Click, MouseMove, Form Load, etc.
.Event procedures
Sum: textBox3.text=CStr(CDbl(textBox1.text)+CDbl(textBox2.text))
Or (CDbl(textBox1.text)+CDbl(textBox2.text)).toString
.Demo: Text alignment (TextAlign property)

9. Using VB Functions or .Net Methods?
VB functions: Cstr, Cdbl, …
.Net framework:
System.Convert

10. VB Projects
A VB project consists of several files. Visual Studio .Net automatically creates a project folder to keep all project files in the folder.
Project file
Form file
Modules
Class file
Etc.

11. Configure VB Project Project property page Tools/Options Application
Compile
References
Tools/Options
Environment
Projects and Solutions
VB defaults

12. VB Defaults Option Explicit: Option Strict: Option Compare:
On --- must declare variables before use
Option Strict:
Off VB will convert the data
Option Compare:
Binary --- case sensitive
Text case insensitive

13. Variable Declarations
Option Explicit
Dim variableName as DataType
Variable naming rules:
The first character must be a letter or an underscore character.
Use only letters, digits, and underscore.
Cannot contain spaces or periods.
No VB keywords
Naming conventions:
Descriptive
Consistent lower and upper case characters.
Ex. Camel casing: lowerUpper, employeeName

14. Control Naming Conventions
The first three letters should be a lowercase prefix that indicates the control’s type.
frm, txt, lbl, btn.
The first letter after the prefix should be uppercase.
txtSalary, lblMessage
The part of the control name after the prefix should describe the control’s purpose in the application.

15. VB Data Types Boolean (True/False): 2 bytes
Byte: Holds a whole number from 0 to 255.
Char: single character
Date: date and time, 8 bytes.
Decimal: Real number up to 29 significant digits, 16 bytes
Double: real, 8 bytes
Single: real, 4 bytes
Integer: 4 bytes (int32, uint32)
Long: 8 bytes integer
Short: 2 bytes integer
String
Object: Holds a reference of an object

16. Variable Declaration Examples
Dim empName as String
Declare multiple variables with one Dim:
Dim empName, dependentName, empSSN as String
Dim X As Integer, Y As Single
Initiatialization
Dim interestRate as Double =

17. Variable Default Value
Variables with a numeric data type: 0
Boolean variables: False
Date variables: 12:00:00 AM, January 1 of the year 1.
String variables: Nothing

18. Variable Scope
Block-level scope: declared within a block of code terminated by an end, loop or next statement.
If city = “Rome” then
Dim message as string = “the city is in Italy”
MessageBox.Show(message)
End if
Procedural-level scope: declared in a procedure
Class-level, module-level scope: declared in a class or module but outside any procedure with either Dim or Private keyword.
Project-level scope: a module variable declared with the Public keyword.

19. Data Conversion
Implicit conversion: When you assign a value of one data type to a variable of another data type, VB attempts to convert the value being assigned to the data type of the variable if the OptionStrict is set to Off.
Explicit conversion:
VB.Net Functions: CStr, Ccur, CDbl, Cint, CLng, CSng, Cdate,Val, etc.
.Net System.Convert
Type class’s methods:
toString

20. Date Data Type
Variables of the Date data type can hold both a date and a time. The smallest value is midnight (00:00:00) of Jan 1 of the year 1. The largest value is 11:59:59 PM of Dec. 31 of the year 9999.
Date literals: A date literal may contain the date, the time, or both, and must be enclosed in # symbols:
#1/30/2003#, #1/31/2003 2:10:00 PM#
#6:30 PM#, #18:30:00#
Note: ControlPanel/RegionalOptions/Date

21. Date Literal Example:
Dim startDate as dateTime
startDate = #1/30/2003#
Use the System.Convert.ToDateTime function to convert a string to a date value:
startDate = System.Convert.ToDateTime(“1/30/2003”)
If date string is entered in a text box:
startDate = System.Convert.ToDateTime(txtDate.text)
Or startDate=Cdate(txtDate.text)
Date data type format methods

22. Some Date Functions Now: Current date and time Today: Current date
TimeOfDay
DateDiff:
Demo
Days between two dates
Days to Christmas
DateDiff(DateInterval.Day, Today(), #12/25/2007#)
Date data type properties and methods

23. Using Online Help Example:Search Help for DateDiff
MSDN
Visual Basic
Reference 
Language reference
Functions:
DateDiff Function

24. Arithmetic and String Operators
+, -, *, /. \, ^
String Concatenation: &, +
Compound operator:
: X= X+1 or X +=1

25. IF Statement IF condition THEN statements [ELSEIF condition-n THEN
[elseifstatements]
[ELSE
[elsestatements]]]
End If

26. Select Case Structure SELECT CASE testexpression
[CASE expressionlist-n
[Statements]
[CASE ELSE
[elsestatements]
END SELECT

27. Select Case Example SELECT CASE temperature CASE <40
Text1.text=“cold”
CASE < 60
Text1.text=“cool”
CASE 60 to 80
Text1.text=“warm”
CASE ELSE
Text1.text=“Hot”
End Select

28. Loop FOR index – start TO end [STEP step] [statements] [EXIT FOR]
NEXT index
DO [{WHILE| UNTIL} condition]
[EXIT DO]
LOOP

29. Do While/Do Until Private Sub Command1_Click() Dim counter As Integer
Do While counter <= 5
Debug.write(counter)
counter = counter + 1
Loop
Text1.Text = counter
End Sub
Private Sub Command2_Click()
Do Until counter > 5

30. With … End With
Convenient shorthand to execute a series of statements on a single object. Within the block, the reference to the object is implicit and need not be written.
With TextBox1
.Height = 250
.Width = 600
.Text = “Hello”
End With

31. . Sub procedure: Procedures Sub SubName(Arguments) … End Sub
To call a sub procedure SUB1
CALL SUB1(Argument1, Argument2, …)

32. Function Or Private Function tax(salary) As Double tax = salary * 0.1
End Function Or
Private Function tax(salary)
Return salary * 0.1

33. Call by Reference Call by Value
The address of the item is passed. Any changes made to the passing variable are made to the variable itself.
ByVal
Default
Only the variable’s value is passed.

34. ByRef, ByVal example
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim myStr As String
myStr = TextBox1.Text
Call ChangeTextRef (myStr)
TextBox1.Text = myStr
End Sub
Private Sub ChangeTextRef(ByRef strInput As String)
strInput = "New Text"