'Delete-Taste gedrückt
    Private Sub ComboBox1_KeyDown(ByVal sender As System.Object, ByVal e As  _
      System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyDown
        If e.KeyCode = Keys.Delete Then
            If ComboBox1.DroppedDown = True Then
                If ComboBox1.Items.Count = 1 Then
                    ComboBox1.Enabled = False
                    'ComboBox1.SelectedIndex = -1
                    'ComboBox1.Text = ""
                Else
                    If ComboBox1.SelectedIndex > -1 Then
                        ComboBox1.Items.RemoveAt(ComboBox1.SelectedIndex)
                    End If
                End If
            End If
        End If
    End Sub