For Each blackcount As String In Blacklist
    If text.Contains(blackcount) Then
       tslBlack.Text = blackcount
       tslEingangzeit.Text = TimeOfDay
          If modAllgemeinHaupt.Diaganz = True Then
             msg = ""
             text = ""
          Else
             For Each whitecount As String In Whitelist
                If text.Contains(whitecount) Then
                   entfernt = text.Remove(0, Zeichenentfernen)
                   txtMeldung.Text = entfernt
                   txtMeldung.Select(Len(txtMeldung.Text), 0)
                   tslStichwort.Text = whitecount
                   tslEingangzeit.Text = Now
                   IO.File.AppendAllText("C:\Protokoll.txt", text)
                   msg = ""
                   text = ""
                End If
             Next whitecount
          End If
       Next blackcount

        For Each blackcount As String In Blacklist
            If Text.Contains(blackcount) Then
                tslBlack.Text = blackcount
                tslEingangzeit.Text = TimeOfDay
                If modAllgemeinHaupt.Diaganz = True Then
                    msg = ""
                    text = ""
                End If
            Else
                For Each whitecount As String In Whitelist
                    If text.Contains(whitecount) Then
                        entfernt = text.Remove(0, Zeichenentfernen)
                        txtMeldung.Text = entfernt
                        txtMeldung.Select(Len(txtMeldung.Text), 0)
                        tslStichwort.Text = whitecount
                        tslEingangzeit.Text = Now
                        IO.File.AppendAllText("C:\Protokoll.txt", text)
                        msg = ""
                        text = ""
                    End If
                Next whitecount
            End If
        Next blackcount
    End Function

        For Each blackcount As String In Blacklist
            If text.Contains(blackcount) Then
                b = 1
            Else
                b = 0
            End If
        Next blackcount
 
        For Each whitecount As String In Whitelist
            If text.Contains(whitecount) Then
                w = 1
            Else
                w = 0
            End If
        Next
 
        If b = 1 And w = 1 Then
            text = ""
            msg = ""
        ElseIf b = 1 And w = 0 Then
            text = ""
            msg = ""
        ElseIf b = 0 And w = 1 Then
            txtMeldung.Text = text
            text = ""
            msg = ""
        Else
            text = ""
            msg = ""
        End If

For Each blackcount As String In Blacklist
    If text.Contains(blackcount) Then
         'Hier etwas tun
          Else
             For Each whitecount As String In Whitelist
                If text.Contains(whitecount) Then
                 'Tu hier etwas
                End If
             Next whitecount
          End If
       Next blackcount

        Dim IsInBlack, IsInWhite As Boolean 'Init = false
 
        For Each blackitem As String In blacklist
            If text.Contains(blackitem) Then IsInBlack = True : Exit For
        Next
 
 
        For Each whiteitem As String In whitelist
            If text.Contains(whiteitem) Then IsInWhite = True : Exit For
        Next
 
        If Not IsInBlack AndAlso IsInWhite Then
            '..............
        End If

        For Each blackitem As String In blacklist
            If text.Contains(blackitem) Then IsInBlack = True : Exit For
        Next
 
 
        For Each whiteitem As String In whitelist
            If text.Contains(whiteitem) Then IsInWhite = True : Exit For
        Next
 
        If Not IsInBlack AndAlso IsInWhite Then
            'z.B:
            MsgBox "Whiteitem"
        End If

    Dim IsInBlack, IsInWhite As Boolean
    Dim blackitem As String = "", whiteitem As String = ""
 
    For Each blackitem In blacklist
        If text.Contains(blackitem) Then IsInBlack = True : Exit For
    Next
 
 
    For Each whiteitem In whitelist
        If text.Contains(whiteitem) Then IsInWhite = True : Exit For
    Next
 
    If Not IsInBlack AndAlso IsInWhite Then
       Dim it As String = whiteitem
    End If

Zitat:

Nun möchte ich diese Testmeldung Ausschließlich dann Anzeigen lassen, wenn eines der WL- Stichworte aber KEINES der BL- Worte enthalten ist.

if whitelist.Any(addressof text.Contains) andalso not blacklist.Any(addressof _
  text.Contains) then messagebox.show(text)

(Rechtschreibfehler urheberrechtlich geschützt)

''' <summary>Suche im Text nach dem Listenindex des ersten Wortes, 
'''  das in der Wortliste enthalten ist</summary>
''' <param name="Text">zu durchsuchender Text</param>
''' <param name="SplitStrings">"Trennzeichen zwischen den Worten im Text</param>
''' <param name="wordlist">Liste mit Worten, nach denen zu suchen ist</param>
''' <param name="Ignorecase">Groß-/Kleinschreibung bei Suche ignorieren?</param>
''' <returns>Listen-Index des ersten gefundenen Wortes (oder -1) </returns>
Public Function IndexOfWord(ByVal text As String, _
                            ByVal wordlist As Collections.Generic.List(Of _
                            String), _
                   Optional ByVal SplitStrings() As String = Nothing, _
                   Optional ByVal Ignorecase As Boolean = False) As Integer
 
    'Eingaben prüfen
    If wordlist Is Nothing OrElse wordlist.Count = 0 Then Return -1
    If String.IsNullOrEmpty(text) Then Return -1
 
    If SplitStrings Is Nothing OrElse SplitStrings.Count = 0 Then
       SplitStrings = {" "} 'Default-Trennzeichen zwischen Worten
    End If
 
    'Text und Wortliste für den internen Gebrauch umsetzen
    Dim ilist As New Collections.Generic.List(Of String)
    Dim itext As String = ""
 
    If Ignorecase Then
       itext = text.ToLower
       For i As Integer = 0 To wordlist.Count - 1
          ilist.Add(wordlist(i).ToLower)
       Next i
    Else
       itext = text
       ilist = wordlist       
   End If
 
   'Worte im Text anhand der Trennzeichen ermitteln
   Dim iwords As New Collections.Generic.List(Of String) _
        (itext.Split(SplitStrings, StringSplitOptions.RemoveEmptyEntries))
 
   'die Worte im Text prüfen
   Dim idx As Integer
   For Each wrd As String In iwords
       'Suche nach dem Wortlisten-Index von wrd
       idx = ilist.IndexOf(wrd)
       If idx > -1 Then Return idx 'wrd gefunden
   Next wrd
 
   Return -1 'kein Wort aus dem Text in der Wort-Liste gefunden
End Function