Vb net introduction
This presentation is the property of its rightful owner.
Sponsored Links
1 / 46

VB.Net Introduction PowerPoint PPT Presentation


  • 54 Views
  • Uploaded on
  • Presentation posted in: General

VB.Net Introduction. Visual Studio 2012 Demo. Start page: New project/ Open project/ Recent projects Starting project: File/New Project/ C# /VB/Other language Windows Windows form application Project name/Project folder Project windows: Form design view/Form code view

Download Presentation

VB.Net Introduction

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Vb net introduction

VB.Net Introduction


Visual studio 2012 demo

Visual Studio 2012 Demo

  • Start page: New project/ Open project/Recent projects

  • Starting project:

    • File/New Project/

      • C# /VB/Other language

      • Windows

        • Windows form application

      • Project name/Project folder

  • Project windows:

    • Form design view/Form code view

    • Solution Explorer

      • View/Solution Explorer

    • ToolBox

    • Property Window

      • Properties and Events

    • Server Explorer

    • Project/Add New Item

    • Property window example


  • Introduction to visual basic net

    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


    Vb net introduction

    Form

    • Properties:

      • Name, FormBorderStyle, Text, BackColor, BackImage, Opacity

    • Events:

      • Load, FormClosing, FormClosed

      • GotFocus, LostFocus

      • MouseHover, Click, DoubleCLick


    Common vb net controls

    Common VB.Net Controls

    • TextBox

    • Label

    • Button

    • CheckBox

    • RadioButton

    • ListBox

    • ComboBox

    • PictureBox


    Text box

    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.


    Typical vb net programming tasks

    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.


    To add an event procedure

    To Add an Event-Procedure

    • 1. Select the Properties window

    • 2. Click Events button

    • 3. Select the event and double-click it.

    • Note: Every control has a default event.

      • Form: Load event

      • Button control: Click event

      • Textbox: Text Changed event

    • To add the default event procedure, simply double-click the control.


    Vb net introduction

    Demo

    FirstName

    LastName

    FullName

    .Control properties

    .Event: Click, MouseMove, FormLoad, etc.

    .Event procedures

    FullName: textBox3.Text textBox3.Text = textBox1.Text + " " + textBox2.Text

    Demo: Text alignment (TextBox3.TextAlign=HorizontalAlign.Center)

    TextBox3.BackColor=Color.Aqua


    Vb net introduction

    Demo

    Num1

    Num2

    Sum =

    .Control properties

    .Event: Click, MouseMove, FormLoad, etc.

    .Event procedures

    Sum: textBox3.text=CStr(CDbl(textBox1.text)+CDbl(textBox2.text))

    Or (CDbl(textBox1.text)+CDbl(textBox2.text)).toString


    Data conversion using vb functions or net methods

    Data Conversion Using VB Functions or .Net Methods

    • VB functions: Cstr, Cdbl, …

    • .Net framework:

      • System.Convert

    • TextBox3.Text = (System.Convert.ToDouble(TextBox1.Text) + System.Convert.ToDouble(TextBox2.Text)).ToString


    Configure vb project

    Configure VB Project

    • Project property page

      • Application:

        • Target framework

        • Startup form

      • Compile:

        • Target CPU

        • Option: explicit, strict, compare

      • References

    • Tools/Options

      • Environment


    Vb defaults

    VB Defaults

    • Option Explicit:

      • On --- must declare variables before use

    • Option Strict:

      • Off --- VB will convert the data (implicit conversion)

    • Option Compare:

      • Binary --- case sensitive

      • Text --- case insensitive

    • Option Infer

      • On --- When you set Option Infer to On, you can declare variables without explicitly stating a data type. The compiler infers the data type of a variable from the type of its initialization expression.


    Variable declarations

    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


    Control naming conventions

    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.


    Vb data types

    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


    Variable declaration examples

    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 = 0.0715


    Variable default value

    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


    Arithmetic and string operators

    Arithmetic and String Operators

    • Arithmetic operators:

      +, -, *, /. ^

      \ operator: Divides two numbers and returns an integer result.

      Mod: Divides two numbers and returns only the remainder.

      • Example: 10 mod 3

        .Net Math class:

        Math.Pow(2, 3)

  • String Concatenation: &, +

  • Compound operator:

    :X= X+1 or X +=1


  • Example

    Example

    Dim dividend, divisor, quotient, remainder As Integer

    dividend = CInt(TextBox1.Text)

    divisor = CInt(TextBox2.Text)

    quotient = dividend \ divisor

    remainder = dividend Mod divisor

    TextBox3.Text = quotient

    TextBox4.Text = remainder


    Tostring

    ToString

    • MessageBox.Show("quotient is:" + quotient)

      • Trigger error

    • MessageBox.Show("quotient is:" + quotient.ToString)

    • MessageBox.Show("Remainder is: " + remainder.ToString)

    • Option Strict


    Change machine to return smallest number of coins

    Change Machine to Return Smallest Number of Coins

    Dim changes, quarters, dimes, nickles, pennies As Integer

    changes = CInt(TextBox1.Text)

    quarters = changes \ 25

    dimes = (changes - quarters * 25) \ 10

    nickles = (changes - quarters * 25 - dimes * 10) \ 5

    pennies = changes - quarters * 25 - dimes * 10 - nickles * 5

    TextBox2.Text = quarters

    TextBox3.Text = dimes

    TextBox4.Text = nickles

    TextBox5.Text = pennies


    Fv pv 1 rate year

    FV = PV * (1 +Rate) Year

    Dim PV, Rate, Term, FV As Double

    PV = CDbl(TextBox1.Text)

    Rate = CDbl(TextBox2.Text)

    Term = CDbl(TextBox3.Text)

    FV = PV * (1 + Rate) ^ Term

    TextBox4.Text = FV.ToString("C")


    Formatting numbers with the tostring method

    Formatting Numbers with the ToString Method

    • The ToString method can optionally format a number to appear in a specific way

    • The following table lists the “format strings” and how they work with sample outputs


    Data conversion

    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


    Date data type

    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:

      • #1/29/2013#, #1/31/2013 2:10:00 PM#

      • #6:30 PM#, #18:30:00#


    Date examples

    Date Examples

    • Date Literal Example:

      • Dim startDate as dateTime

      • startDate = #1/29/2013#

    • 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:

      • .ToLongDateString, etc.


    Some date functions

    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(), #7/4/2013#)

      • Date data type properties and methods


    Using online help

    Using Online Help

    • MSDN VB Developer Center

      • http://msdn.microsoft.com/en-us/vstudio/hh388573.aspx

      • Learn/Visual Basic language


    The if then statement

    The If … Then Statement

    • If condition Then

      Statements

    • End If

    • If condition Then

      Statements

      Else

      Statements

    • End If

    • Condition:

      • Simple condition:

        • Comparison of two expressions formed with relational operators:>, <, =, < >, >=, <=

        • Boolean variable

      • Complex condition:

        • Formed with logical operators: ( ), Not, And, Or


    Example1

    Example

    • State University calculates students tuition based on the following rules:

      • State residents:

        • Total units taken <=12, tuition = 1200

        • Total units taken > 12, tuition = 1200 + 200 per additional unit.

      • Non residents:

        • Total units taken <= 9, tuition = 3000

        • Total units taken > 9, tuition = 3000 + 500 per additional unit.


    Decision tree

    Decision Tree

    Units <= 12 or Not

    Resident or Not

    Units <= 9 or Not


    Elseif statement

    ELSEIF Statement

    • IF condition THEN

      statements

      [ELSEIF condition-n THEN

      [elseifstatements]

      [ELSE

      [elsestatements]]]

      End If


    Select case structure

    Select Case Structure

    • SELECT CASE testexpression

      [CASE expressionlist-n

      [Statements]

      [CASE ELSE

      [elsestatements]

      END SELECT


    Select case example

    Select Case Example

    • SELECT CASE temperature

      CASE <40

      TextBox1.text=“cold”

      CASE < 60

      TextBox1.text=“cool”

      CASE 60 to 80

      TextBox1.text=“warm”

      CASE ELSE

      TextBox1.text=“Hot”

      End Select


    Vb net introduction

    The Expression list can contain multiple expressions, separated by commas.

    Select Case number

    Case 1, 3, 5, 7, 9

    textBox1.text=“Odd number”

    Case 2, 4, 6, 8, 10

    textBox1.text=“Even number”

    Case Else

    End Select


    Vb net introduction

    Loop

    • FOR index = start TO end [STEP step]

      [statements]

      [EXIT FOR]

      NEXT index

      DO [{WHILE| UNTIL} condition]

      [statements]

      [EXIT DO]

      LOOP


    Vb net introduction

    Find the Sum of All Even Numbers between 1 and N

    Dim sumEven, myN, i As Integer

    myN = CInt(TextBox1.Text)

    sumEven = 0

    For i = 1 To myN

    If i Mod 2 = 0 Then

    sumEven += i

    End If

    Next

    MessageBox.Show("The sum of even numbers is: " + sumEven.ToString)


    Do while

    Do While

    sumEven = 0

    i = 1

    Do While i <= myN

    If i Mod 2 = 0 Then

    sumEven += i

    End If

    i += 1

    Loop

    MessageBox.Show("The sum of even numbers is: " + sumEven.ToString)


    With end with

    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


    Function

    Function

    Private Function tax(salary) As Double

    tax = salary * 0.1

    End Function

    • Or

      Private Function tax(salary) As Double

      Return salary * 0.1

      End Function


    Procedures

    Procedures

    . Sub procedure:

    Sub SubName(Arguments)

    End Sub

    • To call a sub procedure SUB1

      CALL SUB1(Argument1, Argument2, …)

      • Or

        SUB1(Argument1, Argument2, …)


    Call by reference call by value

    Call by Reference Call by Value

    • ByRef

      • 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.


    Byref example

    ByRef Example

    Private Sub Form3_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim myX, myY As Integer

    myX = 10

    test(myX, myY)

    MessageBox.Show(myY)

    End Sub

    Private Sub test(x As Integer, ByRef y As Integer)

    y = 2 * x

    End Sub


    Byref byval example

    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"

    End Sub


    Variable scope

    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.


  • Login