ANPOP Developers Center > Using ANPOP in Multiple Threading .NET Application

You should download the anpop installer and install it on your machine at first. If you want to distribute or deploy anpop without anpop installer, please click here to learn more.

Why use multi-threading?

Multi-threading application is the ability to execute more that one tasks simultaneous in a single application which subsequently enhance the application performance. 

Create thread in .NET

It is very easy to create thread in .NET application. First you need to define a static (shared) method, this method would be the entry of worker thread. The following code demonstrates how to create a worker thread in Visual Basic.NET

Imports System
Imports System.Threading
Imports ANPOPLib

Public Class SimpleThreadClass
  'The method that will be called when the thread is started
  Public Shared Sub RetrieveEmail()
    Dim oPop3 As New POPMAINClass()
    oPOp3.Connect( "mail.adminsystem.net", "test@adminsystem.net", "test" )
    'Do something
  End Sub 
  Public Shared Sub Main() 
    ' using a ThreadStart delegate.
    Dim t As New Thread(New ThreadStart(AddressOf RetrieveEmail))
    t.Start()
    'Do something
   End Sub 'Main
End Class

Now, we can use ANPOP to retrieve email by RetrieveEmail method. As we create multi-threading in this application, we can access multiple pop3 accounts concurrently.

Thread model

Objects of ANPOP are based on Apartment Threading. So we suggest you create each object instance for each thread just like the above sample code. And do not use the object instance which is not created in current thread.

Thread communication and synchronization

How can we transfer data to a sub-thread and how can we assure that the data can only be accessed by one thread? In the following code, we use static ArrayList to share data in sub-thread and lock data via Mutex.

Imports System
Imports System.Threading
Imports ANPOPLib

Public Class SimpleThreadClass

  Public Class Pop3AccountClass
    Public m_pop3Server As String
    Public m_userName As String
    Public m_password As String
  End Class
  
  Private Shared m_hMutex As New Mutex(False)
  Private Shared m_arTaskList As New ArrayList()	
	
  'The method that will be called when the thread is started
  Public Shared Sub RetrieveEmail()
    Dim oPop3 As New POPMAINClass()
    Dim pop3Account As Pop3AccountClass
    Do While True
      pop3Account = PopAccount() 'Get pop3 account from ArrayList
      If Not(pop3Account Is Nothing) Then
        oPOp3.Connect( pop3Accout.m_pop3Server, _
                         pop3Account.m_userName, pop3Account.m_password )
        'Do something
      Else
        Thread.Sleep( 100 )
      End If
    Loop 
  End Sub 
  
  'Lock ArrayList
  Private Shared Sub LockTaskList()
    m_hMutex.WaitOne()
  End Sub
  
   'Unlock ArrayList
  Private Shared Sub UnlockTaskList()
    m_hMutex.ReleaseMutex()
  End Sub

   'Push a pop3 account into ArrayList	
  Public Shared Function PushAccount(ByRef pop3Account As Pop3AccountClass)
    LockTaskList()
    m_arTaskList.Add(pop3Account)
    UnlockTaskList()
  End Function
  
  'Pop a pop3 account from ArrayList	  
  Public Shared Function PopAccount() As Pop3AccountClass
    LockTaskList()
    If m_arTaskList.Count > 0 Then
      PopAccount = m_arTaskList(0)
      m_arTaskList.RemoveAt(0)
    Else
      PopAccount = Nothing
    End If
    UnlockTaskList()
  End Function
			  
  Public Shared Sub Main() 
    ' create a worker thread, of course you can create multiple worker threads here
    Dim t As New Thread(New ThreadStart(AddressOf RetrieveEmail))
    t.Start()
    
    Dim pop3Account As New Pop3AccountClass
    pop3Account.m_pop3Server = "mail.adminsystem.net"
    pop3Account.m_userName = "test@adminsystem.net"
    pop3Account.m_password = "test"
    
    PushAccount( pop3Account ) 'submit a pop3 account to sub-thread
    'submit other accounts to sub-thread.
   
   End Sub 'Main
End Class	
	

Full Sample

Please refer to POP3QUEUE in ANPOP installation package.

Free Email Support

Not enough? Please contact our technical support team.

Support@EmailArchitect.NET
VIP@EmailArchitect.NET(Registered User)

Remarks
We usually reply emails in 24hours. The reason for getting no response is likely that your smtp server bounced our reply. In this case, please try to use another email address to contact us. Your Hotmail or Yahoo email account is recommended.