Imports System.IO
Imports System.Net
Imports System.Text
Imports System.Text.RegularExpressions
Imports System.Collections.Generic
Imports System.Linq
Imports System.Threading.Tasks
 
Public Class Form1
 
    Dim cookieCon As New CookieContainer
    Dim request As HttpWebRequest
    Dim TokenString As String
    Dim Quelltext As String
    Dim WithEvents myWebClient As New WebClient
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
 
        myWebClient = New CookieAwareWebClient()
        Quelltext = myWebClient.DownloadString("http://blabla")
 
    End Sub
 
  'Property um auf cookieCon von außerhalb der Klasse zugreifen zu können 
  WriteOnly Property CC As CookieContainer
     Set(ByVal value As CookieContainer)
       cookieCon = value
     End Set
  End Property
 
 
End Class
 
Class CookieAwareWebClient
 
    Inherits WebClient
    Private ReadOnly cookies As New CookieContainer()
    Protected Overrides Function GetWebRequest(ByVal address As Uri) As _
      WebRequest
        Dim request As WebRequest = MyBase.GetWebRequest(address)
        Dim webRequest As HttpWebRequest = TryCast(request, HttpWebRequest)
        If webRequest IsNot Nothing Then
            webRequest.CookieContainer = cookies
            'Wert von cookies mit der Property von Form1 setzen
            Form1.CC = cookies
        End If
        Return request
    End Function
 
End Class