VB.Net/Language Basics/Const — различия между версиями

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Текущая версия на 12:42, 26 мая 2010

Const Variable for Constant

Imports System
public class MainClass
    Shared Sub Main()
         Const FreezingPoint As Integer = 32 
         Const BoilingPoint As Integer = 212
         Console.WriteLine("Freezing point of water: {0}",FreezingPoint)
         Console.WriteLine("Boiling point of water: {0}", BoilingPoint)
    End Sub
End Class


Const Variable in a Function

Imports System
Public Class MainClass
    Shared Sub Main(ByVal args As String())
       Const FreezingPoint As Integer = 32 " degrees Farenheit
       Const BoilingPoint As Integer = 212
       System.Console.WriteLine("Freezing point of water: {0}", FreezingPoint)
       System.Console.WriteLine("Boiling point of water: {0}", BoilingPoint)
    End Sub
End Class


Define and use Const

Imports System
Imports System.Diagnostics
Public Class MainClass
    Public Enum AccessLevel
        Clerk
        Supervisor
        Administrator
        User = Clerk
        Manager = Supervisor
        SysAdmin = Administrator
        Superuser = Administrator
    End Enum
    Private Const MAX_VALUES As Integer = CInt(123.45)
    Private Const MASK_READ As Long = &H1000&
    Private Const MASK_WRITE As Long = &H2000&
    Private Const MASK_READ_WRITE As Long = MASK_READ Or MASK_WRITE
    Private Const MAX_ACCESS_LEVEL As AccessLevel = AccessLevel.SuperUser
    Shared Sub Main()
        
        Console.WriteLine("MAX_VALUES:" & MAX_VALUES)
        Console.WriteLine("MASK_READ"   & MASK_READ)
        Console.WriteLine("MASK_WRITE " & MASK_WRITE)
        Console.WriteLine("MASK_READ_WRITE " & MASK_READ_WRITE)
        Console.WriteLine("MAX_ACCESS_LEVEL " & MAX_ACCESS_LEVEL)
    End Sub
End Class


Define and use Const value

Imports System
Public Class MainClass
    Private Const strFileName As String = "test.txt"
    Shared Sub Main()
        System.Console.WriteLine(strFileName)
    End Sub
End Class


String Const Demo

Imports System
Public Class MainClass
    Public Const AConst As String = "String"
    Shared Sub Main(ByVal args As String())
       Console.WriteLine(AConst)
    End Sub
    
End Class