VB.Net/Class/Shared

Class Shared Variable

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

   Shared Sub Main(ByVal args As String())
     Console.WriteLine("Students before instantiation: " & Student.Count)
     Dim student1 As Student = New Student("A", "B")
     Dim student2 As Student = New Student("C", "D")
     " output of student2 after instantiation
     Console.WriteLine("Students after instantiation: " & vbCrLf & _
        "via Student.Count: " & Student.Count)
     " display name of first and second student
     Console.WriteLine(vbCrLf & "Students 1: " & _
        student1.FirstName & " " & student1.LastName & _
        vbCrLf & "Student 2: " & student2.FirstName & " " & _
        student2.LastName)
     " mark student1 and student2 for garbage collection
     student1 = Nothing
     student2 = Nothing
     System.GC.Collect() " request garbage collection
     
   End Sub

End Class " Class Student uses Shared variable. Class Student

  Inherits Object
  Private mFirstName As String
  Private mLastName As String
  " number of objects in memory
  Private Shared mCount As Integer
  " Student constructor
  Public Sub New(ByVal firstNameValue As String, _
     ByVal lastNameValue As String)
     mFirstName = firstNameValue
     mLastName = lastNameValue
     mCount += 1 " increment shared count of students
     Console.WriteLine _
        ("Student object constructor: " & mFirstName & _
        " " & mLastName)
  End Sub " New
  " finalizer method decrements Shared count of students
  Protected Overrides Sub Finalize()
     mCount -= 1 " decrement mCount, resulting in one fewer object
     Console.WriteLine _
        ("Student object finalizer: " & mFirstName & _
        " " & mLastName & "; count = " & mCount)
  End Sub " Finalize
  " return first name
  Public ReadOnly Property FirstName() As String
     Get
        Return mFirstName
     End Get
  End Property " FirstName
  " return last name
  Public ReadOnly Property LastName() As String
     Get
        Return mLastName
     End Get
  End Property " LastName
  " property Count
  Public Shared ReadOnly Property Count() As Integer
     Get
        Return mCount
     End Get
  End Property " Count

End Class " Student

      </source>

Class with all shared Member variables

<source lang="vbnet"> Imports System.IO Module Module1

   Sub Main()
       Console.WriteLine("Today: " & Today.TodayDate)
       Console.WriteLine("Day: " & Today.Day)
       Console.WriteLine("Month: " & Today.Month)
       Console.WriteLine("Year: " & Today.Year)
       Console.WriteLine("Day of week: " & Today.NumericDayOfWeek)
       Console.WriteLine("Day of week: " & Today.StringDayOfWeek)
   End Sub

End Module

   Class Today
       Public Shared TodayDate As DateTime = Now()
       Public Shared Day As Integer = Now.Day()
       Public Shared Month As Integer = Now.Month()
       Public Shared Year As Integer = Now.Year()
       Public Shared NumericDayOfWeek As Integer = Now.DayOfWeek()
       Public Shared StringDayOfWeek As String = Now.DayOfWeek.ToString()
   End Class
          
      </source>

Shared Method Demo

<source lang="vbnet"> Imports System public class MainClass

  Shared Sub Main()
       Dim c1 As New C()
       Dim c2 As New C()
       c2.Test()
       c.SharedTest()
  End Sub

End Class Class C

   Public Shared Sub SharedTest()
       Static x As Integer
       x = x + 1
       console.WriteLine(x)
   End Sub
   Public Sub Test()
       Static x As Integer
       x = x + 1
       console.WriteLine(x)
   End Sub

End Class

      </source>

User Shared variable to count instance number

<source lang="vbnet"> Imports System.IO Module Module1

   Sub Main()
       Dim p As New Professor()
       Console.WriteLine("count {0}", p.Count)
       Dim pp As New Professor()
       Console.WriteLine("count {0}", pp.Count)
   End Sub

End Module

   Class Professor
       Public Shared Count As Integer = 0
       Public Name As String
       Private Age As Integer
       Public OfficeNumber As String
       Private HomePhone As String
       Public Sub New()
           Count = Count + 1
       End Sub
       
   End Class
          
      </source>

Use Shared method to construct Object

<source lang="vbnet"> Imports System Imports System.Drawing Imports System.Data Imports System.IO Imports System.Collections Imports System.Windows.Forms Imports System.Drawing.Printing Public Class MainClass

   Shared Sub Main()
      Dim newUser As User
      newUser = User.CreateUser("Joe", "password15")
      Console.WriteLine(newUser.Username)
   End Sub

End Class

Public Class User

   Public Username As String
   Private password As String

   Public Shared Function CreateUser(ByVal username As String, _
                    ByVal password As String) As User
       Dim user As New User()
       user.Username = username
       user.Password = password
       Return user
   End Function

End Class

      </source>