Private Sub fidBundeslandTextBox_TextChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles fidBundeslandTextBox.TextChanged
        If fidBundeslandTextBox.Text.Length = 0 Then
            BundeslandComboBox.SelectedIndex = -1
        Else
            BundeslandComboBox.SelectedValue = CObj(fidBundeslandTextBox.Text)
        End If
    End Sub
    'wenn der Wert in ComboBox sich ändert - wird entsprechen auch´der Wert im 
    ' Textbox geändert
    Private Sub BundeslandComboBox_SelectedIndexChanged(ByVal sender As _
      System.Object, ByVal e As System.EventArgs) Handles _
      BundeslandComboBox.SelectedIndexChanged
        If BundeslandComboBox.SelectedValue.ToString.Length = 0 Then Exit Sub
        If BundeslandComboBox.Text.Length = 0 Then Exit Sub
        fidBundeslandTextBox.Text = BundeslandComboBox.SelectedValue.ToString
    End Sub