Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim dtbl As New System.Data.DataTable
        dtbl = Form1.DataSet1.Tables(Form1.ListBox1.SelectedItem)
        With dtbl
            For r As Double = 0 To .Rows.Count - 1
                If CType(.Rows(r).Item("P_ARTICLE_DESCR3"), String).StartsWith( _
                  "??_??@") Then
                    'Ersetzung durchführen
                    .Rows(r).Item("P_ARTICLE_DESCR3") = .Rows(r).Item( _
                      "P_ARTICLE_DESCR3").ToString.Replace("??_??@", "")
                End If
 
            Next r
        End With
 
 
    End Sub