C# と VB.NET の質問掲示板

ランダムに変化する場合を書きかえてみましたが、これでは反転しません。
う〜ん。どうしてかな？(T_T)
Public Class Form1
    Dim number As Integer
    Dim rn As Random = New Random()

    
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

        PictureBox1.Top = rn.Next(400)
        number = rn.Next(10)

       
        If PictureBox1.Left < 0 Or PictureBox1.Left > Me.Width Then
            number *= -1
            PictureBox1.Left += number
        Else
            PictureBox1.Left += number


        End If

    End Sub

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


        Timer1.Enabled = Not Timer1.Enabled



    End Sub


   
End Class