VB.Net - Directives

#Const constname = expression

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#Const state = "WEST BENGAL"

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Example

Module mydirectives
#Const age = True
Sub Main()
   #If age Then
      Console.WriteLine("You are welcome to the Robotics Club")
   #End If
   Console.ReadKey()
End Sub
End Module

						
The #ExternalSource Directive

#ExternalSource( StringLiteral , IntLiteral )
    [ LogicalLine ]
#End ExternalSource

						
Example

Module mydirectives
    Public Class ExternalSourceTester

        Sub TestExternalSource()

        #ExternalSource("c:\vbprogs\directives.vb", 5)
            Console.WriteLine("This is External Code. ")
        #End ExternalSource

        End Sub
    End Class

    Sub Main()
        Dim t As New ExternalSourceTester()
        t.TestExternalSource()
        Console.WriteLine("In Main.")
        Console.ReadKey()

    End Sub

						
The #If...Then...#Else Directives

#If expression Then
   statements
[ #ElseIf expression Then
   [ statements ]
...
#ElseIf expression Then
   [ statements ] ]
[ #Else
   [ statements ] ]
#End If

						

#Const TargetOS = "Linux"
#If TargetOS = "Windows 7" Then
   ' Windows 7 specific code
#ElseIf TargetOS = "WinXP" Then
   ' Windows XP specific code
#Else
   ' Code for other OS
#End if

						
Example

Module mydirectives
#Const classCode = 8

   Sub Main()
   #If classCode = 7 Then
        Console.WriteLine("Exam Questions for Class VII")
   #ElseIf classCode = 8 Then
        Console.WriteLine("Exam Questions for Class VIII")
   #Else
        Console.WriteLine("Exam Questions for Higher Classes")
   #End If
        Console.ReadKey()

    End Sub
End Module

						
The #Region Directive

#Region "identifier_string" 
#End Region

						

#Region "StatsFunctions" 
    ' Insert code for the Statistical functions here.
#End Region