Dim g As Graphics
 
    Protected Overrides Sub OnLoad(ByVal e As System.EventArgs)
        MyBase.OnLoad(e)
        Dim b As Bitmap = New Bitmap(PictureBox1.Width, PictureBox1.Height)
        PictureBox1.Image = b
        g = Graphics.FromImage(b)
    End Sub
 
    Dim lp As New Point(-1, -1)
 
    Private Sub PictureBox1_MouseLeave(ByVal sender As Object, ByVal e As _
      System.EventArgs) Handles PictureBox1.MouseLeave
        lp = New Point(-1, -1)
    End Sub
 
    Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
        Dim np As New Point(e.X, e.Y)
        If lp.X > -1 Then
            g.DrawLine(Pens.Black, lp, np)
        End If
        lp = np
        PictureBox1.Refresh()
    End Sub

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