Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button2.Click
        GetPoints()
End Sub
    Sub GetPoints()
        CheckPoint.Clear()
        Dim x As Int32
        Dim p As Point
        For t As Double = 0.1 To 0.9 Step 0.1
            x = bzpoints(0).X + t * (bzpoints(3).X - bzpoints(0).X)
            For i As Double = 1 To 0 Step -0.001
                p.X = bzpoints(0).X * i ^ 3 + bzpoints(1).X * 3 * i ^ 2 * (1 - _
                  i) + bzpoints(2).X * 3 * i * (1 - i) ^ 2 + bzpoints(3).X * (1 _
                  - i) ^ 3
                p.Y = bzpoints(0).Y * i ^ 3 + bzpoints(1).Y * 3 * i ^ 2 * (1 - _
                i) + bzpoints(2).Y * 3 * i * (1 - i) ^ 2 + bzpoints(3).Y * (1 - _
                i) ^ 3
                If p.X >= x Then
                    CheckPoint.Add(p)
                    Exit For
                End If
            Next
        Next
        Refresh()
    End Sub