PRivate Sub Btn_click(sender ...)
Dim mnu as new contextmenu
 
    AddHandler CType(mnu.MenuItems.Add("ein eintrag"), MenuItem).Click, _
      AddressOf       Me.OpenFile
 
        btn.ContextMenu = Nothing
        btn.ContextMenu = mnu
        btn.ContextMenu.Show(btn, New Point(btn.Width, 0))
End Sub
 
    Private Sub OpenFile(ByVal sender As Object, ByVal e As System.EventArgs)
        MessageBox.show(CType(sender, MenuItem).Text)
    End Sub