Visual Basic 2008 9.0 .NET Examples and Ebook

Local variables have scopes limited to the statementblock in which they are declared.

ifVariable can only be accessed between If and Else.
elseVariable can only be accessed between Else and End If.
caseVariable can only be accessed in Case 1.
doVariable can only be accessed between Do and Loop.
forVariable1 and forVariable2 can only be accessed between For and Next.
forEachVariabele1 and forEachVariabele2 can only be accessed between For Each and Next.

Module Example1
    Sub Main()
        Dim someCondition As Boolean
        If someCondition Then
            Dim ifVariable As Integer
            '...
        Else
            Dim elseVariable As Integer
            '...
        End If
        '
        Dim someExpression As Integer
        Select Case someExpression
            Case 1
                Dim caseVariable As Integer
        End Select
        '
        Do
            Dim doVariable As Integer
            '...
        Loop
        '
        For forVariable1 As Integer = 1 To 10
            Dim forVariable2 As Integer
            '...
        Next
        '
        Dim someCollection As Integer()
        For Each forEachVariable1 As Integer In someCollection
            Dim forEachVariable2 As Integer
            '...
        Next
    End Sub
End Module

Although it seem like some declaration are repeated ( declarations of _-
doVariable, forVariable2 and forEachVariable2 ), they are declared only once. These variables keep there values for next executions of the

Module Example2
    Sub Main()
        For count As Integer = 1 To 5
            Dim forVariable As Integer
            Console.WriteLine(forVariable)
            forVariable += 1
        Next
        Console.WriteLine()
        '
        For count As Integer = 1 To 5
            Dim forVariable As Integer = 1
            Console.WriteLine(forVariable)
            forVariable += 1
        Next
        '
        Console.ReadLine()
    End Sub
End Module

Output :

 0
 1
 2
 3
 4

 1
 1
 1
 1
 1