Public Class Form1
    Dim abbruch As Boolean
    Dim zaehler As Int32
 
    Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If e.KeyCode = Keys.Escape Then
            abbruch = True
        End If
    End Sub
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.KeyPreview = True
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Do
            zaehler += 1
            Me.Text = zaehler
            Application.DoEvents()
            Threading.Thread.Sleep(20)
        Loop Until abbruch               'Abbruch wenn ESC gedrückt wird
    End Sub
End Class