mports System.Drawing.Drawing2D
Public Class Form1
    Dim rpath, gpath, bpath As New GraphicsPath
    Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        If rpath.IsOutlineVisible(e.X, e.Y, New Pen(Color.Black, 5)) = True Then
            rpath.Reset()
            MessageBox.Show("Rote Linie wird gelöscht")
        End If
        If gpath.IsOutlineVisible(e.X, e.Y, New Pen(Color.Black, 5)) = True Then
            gpath.Reset()
            MessageBox.Show("Grüne Linie wird gelöscht")
        End If
        If bpath.IsOutlineVisible(e.X, e.Y, New Pen(Color.Black, 5)) = True Then
            bpath.Reset()
            MessageBox.Show("Blaue Linie wird gelöscht")
        End If
        PictureBox1.Refresh()
    End Sub
    Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
        e.Graphics.DrawPath(Pens.Red, rpath)
        e.Graphics.DrawPath(Pens.Green, gpath)
        e.Graphics.DrawPath(Pens.Blue, bpath)
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        PictureBox1.BackColor = Color.Black
        rpath.AddLine(10, 10, 250, 250)
        gpath.AddLine(10, 100, 250, 100)
        bpath.AddLine(10, 200, 250, 10)
    End Sub
End Class