Imports System.Drawing.Drawing2D
Public Class Form1
    Dim gpath As New GraphicsPath
       Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As _
         System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        Dim testabstand As Int32 = 5
        If gpath.IsOutlineVisible(e.X, e.Y, New Pen(Color.Black, testabstand)) _
          = True Then
            MessageBox.Show("Linie getroffen")
        End If
    End Sub
    Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
        e.Graphics.DrawPath(Pens.Black, gpath)
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.Text = "Linientest"
        Dim g As Graphics = PictureBox1.CreateGraphics
        g.DrawLine(Pens.Black, 50, 10, 250, 250)
        g.DrawLine(Pens.Black, 250, 250, 50, 250)
        g.Dispose()
        gpath.AddLine(50, 10, 250, 250)
        gpath.AddLine(250, 250, 50, 250)
    End Sub
End Class