C# と VB.NET の質問掲示板

具体的なコードは次のようになると思います。
なお，Timerをデザイナで配置するならばFormClosingのTimer1.Disposeはなくてもかまいません。

Public Class Form1

    Dim WithEvents Timer1 As New Timer()

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Me.Timer1.Interval = 1000
        Me.Timer1.Start()
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        Me.Timer1.Stop()
        Me.Timer1.Dispose()
    End Sub

    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Static StringValue As String = String.Empty
        StringValue &= "○"
        e.Graphics.DrawString(StringValue, Me.Font, Brushes.Black, 0, 0)
    End Sub

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

End Class