BCA IPU VB.NET UNIT-II

FEDT VB.NET
F R O N T E N D D E S I G N T O O L
U S I N G
V B . N E T
P R E S E N T A T I O N B Y :
A N K I T V E R M A
( I T D E P A R T M E N T )
A N K I T V E R M A A S S T . P R O F E S S O R
U N I T - 2

28-11-2014 ANKIT VERMA 2
.NET IDE

Elements Of IDE
 Windows Form Designer
 Add control to form, arrange them & add code.
 Properties Window
 Lists properties associated with control.
 Solution Explorer
 Display solution name, project name, form name, fields etc.
 Tool Box
 Provide controls like form, data, components, toolbar, menu etc.
 Object Browser
 Shows the members of object

Elements Of IDE
 Task List Window
 List of errors in source code.
 Server Explorer
 Database connectivity, display tables, views, connections etc.
 Dynamic Help
 Context sensitive help.
 Class View
 Display Classes , methods, properties etc.
 Code & Text Editor Window
 Allow to enter and edit code

STEPS OF WRITING
APPLICATION IN .NET

Steps Of Writing Application In .NET
 Start  Visual Studio 2010

 File  New Project  Select Language VB.NET
 Choose Console or Window Application
Provide
Project Name

 Write Code of program to be made.
 Save Code by click File  Save All
 Press F5 & Run

PROJECT TEMPLATE

Project Templates
 Window Application
 Create application with window interface.
 Class Library
 Create classes to use in other application.
 Console Application
 Create command line application.
 Window Control Library
 Create control for applications.
 Empty Project
 Creating local application.

Project Templates
 Window Service
 Create window service.

VB Terms
 Design Time
 Environment where application being developed.
 Run Time
 Execution of application.
 Forms
 Basic element for creating user interface for application.
 Controls
 Manipulate information.
 Properties
 Control characteristics like color, caption, size etc.

VB Terms
 Methods
 Actions that can be performed by object
 Events
 Action recognized by form or control.
 Generated by user, OS or application.

FEATURES OF VB.NET

Features Of VB.NET
 Simple
 Consistency
 Garbage Collection
 Object Orientation
 Type Safety
 Thread Support
 Structured Exceptional Handling
 Powerful, Flexible, Simplified Data Access
 COM Interoperability

VB vs VB.NET

Similarities Between VB & VB.NET
 Both Are Not Case Sensitive.
 Both Support Windows & Web Based Application.
 Both Are Provided With IntelliSense Feature.

Difference Between VB & VB.NET
VB .NET VB
Object Oriented Object Based
Data Type Declaration Required Not Strongly Typed
Structured Exception Handling Not Structured
Namespace To Organize Classes Not Supported
Automatic Garbage Collection Not Supported
ADO .NET For DB Connectivity DAO, RDO & ADO
Multithreading Not Supported
Console Applications Are Allowed Not Allowed
New Data Type Like Char, Short & Decimal Not Supported
Variable Can Declare In Same Line
Dim a As Integer = 10
Not Allowed
Object Data Type Variant Data Type

Difference Between VB & VB.NET
VB .NET VB
Fixed Length String Not Allowed Allowed
Array Index Start With O Only Array Index Can Be Changed
Set Keyword Not Supported Set Keyword Used To Assign Object
Variables
Passing By Value Is Default For Calling
Procedure
Pass By Reference
Default Properties Of Controls Not
Allowed
Allowed
Return Keyword Used To Return Values name = return value Is Used
Optional Argument Must Be Specified
With Default Value
Not Necessary

DATA TYPE

Data Types Supported In VB.NET
 Number Data Types
 Byte
 Short
 Integer
 Long
 Single
 Double
 Decimal
 Character Data Type
 Char
 String
 Other Data Type
 Boolean
 Date
 User Defined Data Type
e.g. Structure

VARIABLES

Variables
 These Are Area In Memory Referred By Name Or
Identifier During Program Execution.
 Dim a As Integer = 10
 Dim b As Double = 14.01
 Multiple Declaration Is Allowed.
 Dim x , y As Integer
 Constant
 Value not change during execution of code.
 Const a = 45
 Identifier
 Building block of programming language.

Scope Of Variables
 Block Scope
 If block
 Procedure Scope
 Function
 Module
 Class variable accessed by all functions
 Namespace Scope
 Inside namespace
 Shadowing
 Same variable name in two procedures.
 Scope only in module & accessed as FunctionName.Variable

Access Control
 Public
 Private
 Protected
 Friend
 Protected Friend

OPERATORS

Arithmetic Operator
OPRATOR OPERATION
+ Addition
- Subtraction
* Multiplication
/ Float Division
Integer Division
^ Exponentiation
Mod Remainder

Comparison Operator
OPRATOR OPERATION
< Less Than
> Greater Than
= Equality Checking
<> Not Equal To

Assignment Operator
OPRATOR OPERATION
= Assignment
+= Addition With Assignment
-= Subtraction With Assignment
*= Multiplication With Assignment
/= Floating Division With Assignment
= Integer Division With Assignment
^= Exponentiation With Assignment
<= Less Than Equal To
>= Greater Than Equal To

Logical Operator
OPRATOR OPERATION
AND Return True, If Both Operands True
OR Return True, If One or Both Operands True
NOT Return True, If Reverse Logical Value Of Operand
XOR Return False, If Both Operands Either True Or False

CONTROL STRUCTURE

Control Structure
 Program Executes The Statement One After Other.
 Control Structure Change The Flow OF Execution Of
These Statements.
 Control Structure Are Classified Into Three Groups:
 1) Decision Making / Conditional Statements
 2) Looping
 3) Other Statements

1) Decision Making /
Conditional Statements

1) Decision Making / Conditional Statements
 According To Value Of Variable, Control Flow Can Be
Changed For The Execution.
 Two Statements Of This Category:
 If – Else
 Select Case

1) Decision Making : If - Else
 Syntax:
If <condition> Then
[statement]
ElseIf <condition> Then
[statement]
Else
[statement]
EndIf

 Example 1:

 Example 2:

1) Decision Making : Select Case
 Syntax:
Select Case <expression>
Case Value
[statement]
Case Value
[statement]
Case Else
[statement]
End Select

1) Decision Making : Select Case
 Example:

2) Looping

2) Looping
 Execute Statements Repeatedly & Quickly.
 Three Statements Of This Category:
 Do Loop
 While Loop
 For Loop

2) Looping : Do Loop
 Syntax:
Do While <condition>
[statement]
Loop
(OR)
Do Until <condition>
[statement]
Loop
 NOTE: Do Until loop executes only if statement is False.

 Example (Do While):

 Example (Do Until):

2) Looping : While
 Syntax:
While <condition>
[statement]
End While

2) Looping : While
 Example:

2) Looping : For
 Syntax:
For index = start To end Step 1
[statement]
Next

2) Looping : For
 Example:

3) Other Statements

3) Other Statements
 Exit
 Used to exit from loop
 GOTO
 Transfer the control to specified label
 Stop
 Return the program into break mode
 End
 Terminate the program
 Return
 Used in function to return the value to the calling method

3) Other Statement : GoTo , Exit
 Example:

3) Other Statement : Stop, End
 Example:

DATA STRUCTURE

Data Structure In VB .NET
 DS is a way of storing & organizing data in computer,
so that it can be used efficiently.
 Different kind of DS are suited for different kind of
applications.
 Some DS are highly specialized for specific tasks.
 Various DS Are:
 Array
 Array Lists
 Enumeration

1) Array

1) Array
 Array can hold collection of values of same type.
 Element
 Variable in an array is called Element.
 Array has name & its elements can be accessed by
Index or Subscript.
 Array can be single, double or multi dimension.
 Lower Bound (LB) of all dimension array start with O.
 Array is reference type.
 Types of Array:
 Static Array
 Dynamic Array

1) Array : Static Array
 Size of Static Array remain same even at runtime.
 If Array is declared as Object type, we can store
different types of Data Type.
 Syntax:
Dim a(5) As Integer
Dim b(3,5) As String
Dim c( ) As Single = {10.1 , 24.7}
Dim d(3) As Object

1) Array : Static Array
 Example:

1) Array : Dynamic Array
 Size of Dynamic Array changes during execution.
 Used when you don’t know the size of Array.
 Size of Array not provided during declaration.
 Redim
 After declaration no one change the data type .
 Preserve
 Preserve data without losing when dimension of array change.

 Syntax:
Dim a( ) As String
Redim a(5)
Dim b( , ) As Integer
Redim b(3,2)
ReDim Preserve b(3,4)

 Example:
Value Not Lost After
Dimension Change
Because Of Preserve

1) Array : Functions Of Array
 Ubound (arrayname)
 Determine upper bound of array.
 Lbound (arrayname)
 Determine lower bound of array.

2) Array Lists

2) Array Lists
 Flexible Data Structure.
 List can Grow & Shrink dynamically.
 Contain list of values, on which we can perform
operations like Add, Delete etc.

2) Array Lists : Properties & Functions
 Add
 Add an item.
 Insert
 Insert an item at specified position.
 Remove
 Remove an item.
 RemoveAt
 Remove an item from specified position.
 Sort
 Sort items.
 Count
 Count the number of elements.

2) Array Lists
 Example 1:

2) Array Lists
 Example 2:

2) Array Lists
 Example 2 (Output):

3) Enumerations

3) Enumerations
 Enumeration is set of related constants that define a
value type, where each constant is known as member
of Enumeration.
 Work for many constant of same type.
 It set object properties & specify values that are passed
to methods.
 Syntax:
[access modifier] Enum name
<Member List>
End Enum

3) Enumerations
 Example:

PREDEFINED FUNCTIONS

1) MsgBox Function

1) MsgBox Function
 Produce pop-up message box.
 Prompt user to click on command button before he
can continues.
 This function return the result values.

1) MsgBox Function
 Msg=MsgBox(Prompt, Style Value, Title)
 Prompt
 It is message of 1024 (approx.) characters , be displayed to user.
 Style
 Denote the style & type of buttons to display in message box.
 Values
 MsgBoxStyle.YesNoCancel
 MsgBoxStyle.YesNo
 MsgBoxStyle.OkOnly (Default)
 MsgBoxStyle.OkCancel
 MsgBoxStyle.Exclamation
 Title denotes the string displayed in title bar.

1) MsgBox Function
 Result Values Can Be
 MsgboxResult.ok
 MsgboxResult.cancel
 MsgboxResult.abort
 MsgboxResult.retry
 MsgboxResult.ignore
 MsgboxResult.yes
 MsgboxResult.no

1) MsgBox Function
 Example:

2) InputBox Function

 InputBox () function will display a message box where user
enter value or text.
 Return value of function is string type.
 Msg=InputBox(Prompt, Title, default_text, x-position,y-position)
 Prompt
 String expression displayed in dialog box.
 Title
 String expression displayed in title bar.
 Default Text
 Default response when user not provide input.
 X, Y Position
 Indicate the appearance if input box in screen.

 Syntax:

3) Other Function

3) Other Function
FUNCTION USE
Strcomp Comparison for two strings
Lcase Convert String into Lower case
Ucase Convert String into Upper case
Rtrim Remove trailing spaces
Ltrim Remove leading spaces
Trim Remove both leading & trailing spaces
Mid Return specific number of character
Asc Return ASCII code of first letter in a string
Chr Return character of given ASCII code
Now Return current system date time

COMMENTS

Comments
 Comments are explanatory notes included in program
code following a single quotation mark (‘).
 Single Line Comment
 Provide single quotation mark (‘) before line.
 Multiple Line Comment
 Select multiple lines, whom you want to make comment.
 Click Menu Edit  Advance  Comment Selection
 or
 Press Ctrl +K, Ctrl +C

PROCEDURES & FUNCTIONS

Procedures & Functions
 They are group of related commands that perform
certain tasks and also called subprogram.
 Used for repeated task.
 Modular & easy to maintain.
 Easy to debug
 Any changes to code, you have to make changes only in
procedures, not every place of code.
 Subprograms can be invoked from calling block.
 Control transfer to procedure & after execution, return
back to calling procedure.

Procedures & Functions
 Argument which is passed can be variable, constant or
expression.
 You can write the procedure in module, class module
and form module.
 Procedure of class module support OOP concept.
 There are four types of procedure:
 Sub Procedure
 Function Procedure
 Event Procedure
 Invoked according to action associated with controls.
 Property Procedure

1) Sub Procedure

1) Sub Procedure
 Sub Procedure can not return value.
 Parentheses are not optional in VB .NET
 Even no parameters still procedure enclosed using
empty parentheses.
 For calling, procedure name followed by parameters.
 Syntax:
[Access Specifier] sub Name (Arg As DataType, …)
<Statement>
End Sub

1) Sub Procedure
 Example:

2) Function Procedure

 Return a value back to calling program.
 Function can return values in two ways:
 Using Return statement
 Assign value to function name, like VB
 If return data type is not mentioned, Object type will
be default one.
 Function can also called same as procedure.
 Syntax:
[Access Specifier] Function Name (Arg As DataType, …) [As DataType]
<Statement>
End Sub

 Example:

3) Event Procedure

3) Event Procedure
 Events are actions associate with object.
 Foam Load
 Button Click
 Mouse Click
 Events can be raised by user action, by system or by
code itself.
 User can write code to handle events, called event
handling procedures.
 By these procedures, we can call the sub or function
procedures, called implicitly.

PARAMETER PASSING

Passing Parameter
 Code in a procedure needs some information about the
state of the program to do the job.
 These are passed to procedures as arguments.
 There are two ways:
 Pass By Value
 Pass By Reference
28-11-2014 ANKIT VERMA 100

1) Pass By Value
 Default mode of passing arguments.
 Copy of argument is passed to the procedure.
 Any change in value never affect the original variable,
but only affect the copy.
 ByVal keyword is used explicitly, otherwise compiler
automatically inserts this keyword.
 Syntax:
Public Sub disp (ByVal a As Integer)
<statements>
End Sub
28-11-2014 ANKIT VERMA 101

2) Pass By Reference
 Address of argument is passed to procedure.
 Procedure can change its value permanently.
 Procedure have full access to argument.
 ByRef keyword is used.
 Syntax:
Public Sub disp (ByRef a As Integer)
<statements>
End Sub
28-11-2014 ANKIT VERMA 102

3) Optional Argument
 Optional argument is passed to provide some optional
argument with default value.
 If we not pass value of argument, default value will be
substituted.
28-11-2014 ANKIT VERMA 103

4) Named Argument
 Argument data type can’t be changed when we pass the
arguments to procedure.
 Using Named Argument, we can pass the value by
providing Argument Name followed by colon, an equal
sign and argument value.
 Arguments can be passed in any order.
28-11-2014 ANKIT VERMA 104

28-11-2014 ANKIT VERMA 105
CREATING & USING
NAMESPACE

Creating & Using Namespace
 Namespace allows you to create your own namespaces
for holding classes.
 By default classes are created in root namespace that is
based on your project name.
 Syntax:
Namespace <namespace name>
Class <class name>
Members
End Class
End Namespace
28-11-2014 ANKIT VERMA 106

Creating & Using Namespace
 Creating:
 Using
28-11-2014 ANKIT VERMA 107

THANKYOU
P R E S E N T A T I O N B Y :
A N K I T V E R M A
( I T D E P A R T M E N T )
DOUBTS
A N K I T V E R M A A S S T . P R O F E S S O R

BCA IPU VB.NET UNIT-II

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