Visual Basic.NET - contador en visual basic 2010

Boton agregar

':::Total de elementos en el ComboBox

Dim total As Integer = ComboBox1.Items.Count

':::Agregar al ComboBox

ComboBox1.Items.Add(total + 1)

Boton eliminar

':::Total de elementos en el ComboBox

Dim total As Integer = ComboBox1.Items.Count

':::Restar al ComboBox

ComboBox1.Items.Remove(total)

Public Class Form1

    Dim contador As Integer = 1

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        ComboBox1.Items.Add(contador)

        contador = contador + 1

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

        If ComboBox1.Items.Count - 1 >= 0 Then

            ComboBox1.Items.RemoveAt(ComboBox1.Items.Count - 1)

        End If

        If ComboBox1.Items.Count - 1 = 0 Then

            contador = 1

        End If

    End Sub

End Class