Sunday, 22 July 2012

Data type in

DATATYPE in a programming language describes that what type of data a variable can hold. When we declare a variable, we have to tell the compiler about what type of the data the variable can hold or which data type the variable belongs to.

Syntax: Dim VariableName as DataType

VariableName : the variable we declare for hold the values.

DataType : The type of data that the variable can hold

VB.NET sample:

Dim count As Integer

Count: is the variable name

Integer : is the data type

The above example shows, declare a variable 'count' for holding integer values.

In the variable count we can hold the integer values in

The range of -2,147,483,648 to +2,147,483,647.

The follwing are the some of commonly using datatypes in


Boolean variables are stored 16 bit numbers and it can hold only True or false.

VB.NET Runtime type: System.Boolean

VB.NET declaration: dim check as Boolean

VB.NET Initialization: check = false

VB.NET default initialization value: false


Integer variables are stored sighned 32 bit integer values in the range of -2,147,483,648 to +2,147,483,647

VB.NET Runtime type: System.Int32

VB.NET declaration: dim count as Integer

VB.NET Initialization: count = 100

VB.NET default initialization value: 0


String variables are stored any number of alphabetic, numerical, and special characters. Its range from 0 to approximately 2 billion Unicode characters.

VB.NET Runtime type : System.String

VB.NET declaration : Dim str As String

VB.NET Initialization : str = "String Test"

VB.NET default initialization value : Nothing

In VisualBasic.Net we can convert a datatype in two ways. Implicit Conversion and Explicit conversion . Also we can convert a type value to a reference and reference value to a type value. These are called Boxing and unBoxing . Boxing referes value type to reference type and unboxing , reference type ot value type.

Download Source CodePrint Source Code
Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object,
                                ByVal e As System.EventArgs) Handles Button1.Click
        Dim check As Boolean
        check = True
        MsgBox("The value assigned for check is  : " & check)

        Dim count As Integer
        count = 100
        MsgBox("The value holding count is  : " & count)

        Dim str As String
        str = "String test "
        MsgBox("The value holding str is  : " & str)
    End Sub
End Class

When you execute this programme , you will get "true" in the first message box and , 100 in the second message box and "String Test" in the last message box.