Imports System.Windows          'Verweis auf WindowsBase für Vector hinzufügen
Public Class Form1
    Dim WithEvents Pb As New PictureBox With {.Dock = DockStyle.Fill, .Parent = _
      Me}
    Dim Rnd As New Random, Sw As New Stopwatch
    Dim plist As New List(Of PointF)
 
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Me.WindowState = FormWindowState.Maximized
        For i = 1 To 10000  '10.000 Punkte
            plist.Add(New PointF(Rnd.Next(Me.ClientSize.Width), Rnd.Next( _
              Me.ClientSize.Height)))
        Next
    End Sub
 
    Private Sub Pb_MouseMove(sender As Object, e As _
      System.Windows.Forms.MouseEventArgs) Handles Pb.MouseMove
        Sw.Restart()
        Dim v1, v2 As Vector, dist As Double = 2000, nr As Int32
        v1 = New Vector(e.X, e.Y) 'Mausposition
        For i = 0 To plist.Count - 1
            v2 = New Vector(plist(i).X, plist(i).Y)
            If (v1 - v2).Length < dist Then
                dist = (v1 - v2).Length
                nr = i
            End If
        Next
        Sw.Stop()
        Me.Text = "Pt" & nr & ", " & dist.ToString("0.0") & " Pixel" & ",  in " _
          & Sw.ElapsedMilliseconds.ToString & "mSek."
    End Sub
 
    Private Sub Pb_Paint(sender As Object, e As _
      System.Windows.Forms.PaintEventArgs) Handles Pb.Paint
        For i = 0 To plist.Count - 1
            e.Graphics.FillEllipse(Brushes.Black, plist(i).X - 3, plist(i).Y - _
              3, 6, 6)
        Next
    End Sub
End Class