VB.Net/Language Basics/Const

Материал из VB Эксперт
Перейти к: навигация, поиск

Const Variable for Constant

<source lang="vbnet"> 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


      </source>


Const Variable in a Function

<source lang="vbnet"> 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

      </source>


Define and use Const

<source lang="vbnet"> 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

      </source>


Define and use Const value

<source lang="vbnet"> Imports System Public Class MainClass

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

End Class

      </source>


String Const Demo

<source lang="vbnet"> 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

      </source>