structures

Declaration Statements in VB.NET

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Declaration Statements

The declaration statements are used to name and define procedures, variables, properties, arrays, and constants. When you declare a programming element, you can also define its data type, access level, and scope.

The programming elements you may declare include variables, constants, enumerations, classes, structures, modules, interfaces, procedures, procedure parameters, function returns, external procedure references, operators, properties, events, and delegates.

Following are the declaration statements in VB.Net:

S.N Statements and Description Example
1 Dim Statement
Declares and allocates storage space for one or more variables.
Dim number As IntegerDim quantity As Integer = 100Dim message As String = “Hello!”
2 Const Statement
Declares and defines one or more constants.
Const maximum As Long = 1000Const naturalLogBase As Object = CDec(2.7182818284)
3 Enum Statement
Declares an enumeration and defines the values of its members.
Enum CoffeeMugSize    Jumbo    ExtraLarge    Large    Medium    SmallEnd Enum
4 Class Statement
Declares the name of a class and introduces the definition of the variables, properties, events, and procedures that the class comprises.
Class BoxPublic length As DoublePublic breadth As Double   Public height As DoubleEnd Class
5 Structure Statement
Declares the name of a structure and introduces the definition of the variables, properties, events, and procedures that the structure comprises.
Structure BoxPublic length As Double           Public breadth As Double   Public height As DoubleEnd Structure
6 Module Statement
Declares the name of a module and introduces the definition of the variables, properties, events, and procedures that the module comprises.
Public Module myModuleSub Main()Dim user As String = InputBox(“What is your name?”) MsgBox(“User name is” & user)End Sub End Module
7 Interface Statement
Declares the name of an interface and introduces the definitions of the members that the interface comprises.
Public Interface MyInterface    Sub doSomething()End Interface
8 Function Statement
Declares the name, parameters, and code that define a Function procedure.
Function myFunction(ByVal n As Integer) As Double     Return 5.87 * nEnd Function
9 Sub Statement
Declares the name, parameters, and code that define a Sub procedure.
Sub mySub(ByVal s As String)    ReturnEnd Sub
10 Declare Statement
Declares a reference to a procedure implemented in an external file.
Declare Function getUserNameLib “advapi32.dll” Alias “GetUserNameA” (  ByVal lpBuffer As String,   ByRef nSize As Integer) As Integer
11 Operator Statement
Declares the operator symbol, operands, and code that define an operator procedure on a class or structure.
Public Shared Operator +(ByVal x As obj, ByVal y As obj) As obj        Dim r As New obj’ implemention code for r = x + y        Return r    End Operator
12 Property Statement
Declares the name of a property, and the property procedures used to store and retrieve the value of the property.
ReadOnly Property quote() As String     Get         Return quoteString    End Get End Property
13 Event Statement
Declares a user-defined event.
Public Event Finished()
14 Delegate Statement
Used to declare a delegate.
Delegate Function MathOperator(     ByVal x As Double,     ByVal y As Double ) As Double

 

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