Visual Basic

Public Class Puffer
        Private mBuffer As New List(Of DataRow) With {.capacity = 1}

        Property Puffer() As DataRow
            Get
                SyncLock (Me)
                    If mBuffer.Count = 0 Then
                        MsgBox("Alle Puffer sind leer. " & Thread.CurrentThread.Name & " wartet.")
                        Monitor.Wait(Me)
                    End If

                    Dim readValue As DataRow = mBuffer(0)
                    MsgBox(String.Format("{0} liest Element '{1}'.", Thread.CurrentThread.Name, readValue.Item("Name")))
                    OutCounter += 1
                    mBuffer.Remove(mBuffer(0))
                    Monitor.Pulse(Me)
                    Return readValue

                End SyncLock
            End Get

            Set(ByVal WriteValue As DataRow)
                SyncLock (Me)
                    If mBuffer.Count = mBuffer.Capacity Then
                        MsgBox("Alle Puffer sind voll. " & Thread.CurrentThread.Name & " wartet.")
                        Monitor.Wait(Me)
                    End If

                    MsgBox(String.Format("{0} schreibt Element '{1}'.", Thread.CurrentThread.Name, WriteValue.Item("Name")))
                    mBuffer.Add(WriteValue)
                    InCounter += 1
                    Monitor.Pulse(Me)

                End SyncLock
            End Set

        End Property ' Buffer
    End Class

Public Class Producer
       Dim WithEvents ProducerThread As New BackgroundWorker
       Private Puffer As Puffer

       Public Sub New(ByVal sharedObject As Puffer)

           With ProducerThread
               .WorkerReportsProgress = True
               .WorkerSupportsCancellation = True
               .RunWorkerAsync()
           End With
           Puffer = sharedObject

       End Sub

       Public Sub Produce(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles ProducerThread.DoWork
           Thread.CurrentThread.Name = "Produzent"

           'Return a reference to the MAPI layer
           Dim oApp As New Outlook.Application
           Dim oNameSpace As Outlook.NameSpace = oApp.GetNamespace("MAPI")
           ....

           Try
               oNameSpace.Logon(Nothing, Nothing, False, False) ' TODO: Ggf ändern...
               ....
               ' Get Messages collection of Inbox and count them
               Dim oItems As Outlook.Items = oInFolder.Items
               Dim intTotal As Integer = oItems.Count

               ' Loop each unread message.
               For i As Integer = 1 To oItems.Count
                   If ProducerThread.CancellationPending Then Exit Sub

                   If CurrentMedia <> "" Then
                       Dim CurrentRow As DataRow = MailsTable.NewRow()
                       CurrentRow("Absender") = Inquiry.ClientMail
                       ....
                       ' erst einmal in den Puffer
                       Puffer.Puffer = CurrentRow           <----- write into the buffer

                       CurrentRow = Nothing
                   End If
                   oMsg = Nothing
               Next
               oItems = Nothing

           Catch ex As System.Exception
               MsgBox("Fehler in der Routine 'Produce'", MsgBoxStyle.Critical, String.Format("Klasse '{0}'", Me.GetType.Name))

           End Try
       End Sub

       Private Sub ProducerThread_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles ProducerThread.RunWorkerCompleted
           'Thread.CurrentThread.Name = "Produzent"
                 frmProcessOutlAtt.btnRead.Text = "Lesen"

       End Sub
   End Class

Public Class Consumer
        Dim WithEvents ConsumerThread As New BackgroundWorker
        Private Puffer As Puffer
        Private rowCounterValid As Integer
        Private rowCounterInvalid As Integer

        Public Sub New(ByVal sharedObject As Puffer)
            With ConsumerThread
                .WorkerReportsProgress = True
                .WorkerSupportsCancellation = True
                .RunWorkerAsync()
            End With
            Puffer = sharedObject
        End Sub

        Public Sub Consume(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles ConsumerThread.DoWork
            MailsTable.Clear()
            Dim DA As m2prolapDataSetTableAdapters.AdressenTableAdapter = New m2prolapDataSetTableAdapters.AdressenTableAdapter
            Try
                If ConsumerThread.CancellationPending then Exit Sub

                Dim myrow As DataRow = Puffer.Puffer           <----- read from the buffer
                While myrow IsNot Nothing
                    If DA.GetDataByNamesStreetsMail(myrow("Name"), myrow("Strasse"), myrow("Vorname"), myrow("Absender")).Count > 0 Then
                        rowCounterValid += 1
                        myrow("Antworten") = False
                        ConsumerThread.ReportProgress(1, myrow)
                    Else
                        rowCounterInvalid += 1
                        myrow("Antworten") = True
                        ConsumerThread.ReportProgress(0, myrow)
                    End If

                    myrow = Puffer.Puffer
                End While

            Catch ex As System.Exception
                MsgBox("Fehler in der Routine 'Consume'", MsgBoxStyle.Critical, String.Format("Klasse '{0}'", Me.GetType.Name))

            End Try

        End Sub

        Private Sub ConsumerThread_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles ConsumerThread.ProgressChanged
            Dim myRow As DataRow = e.UserState
            Dim Marker As Boolean = CBool(e.ProgressPercentage)
            MailsTable.Rows.Add(myRow)

            With frmProcessOutlAtt
                .DataGrid.DataSource = MailsTable
                .DataGrid.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.DisplayedCells)
                .DataGrid.Refresh()
            End With

            'MessageBox.Show(String.Format("Datensatz '{0}' wurde ausgewertet.", myRow("Name")))
            'OutCounter = MailsTable.Rows.Count

        End Sub

        'THIS ONE IS NOT FIRED AT ALL:
        Private Sub ConsumerThread_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles ConsumerThread.RunWorkerCompleted
            Thread.CurrentThread.Name = "Konsument"
            MsgBox(String.Format("{0} Datensätze von {1} verarbeitet." & vbCrLf & "{1} ist beendet.", _
                                 OutCounter, Thread.CurrentThread.Name), MsgBoxStyle.Information)
        End Sub
    End Class