>Hi All,
>
>How to determine if a property of an object is changed automatically, such as Listbox.Listcount, form.activeobject, I've tried to use assign method, but it didn't work.
>

I don't think you can do this. For user assigned propreties, you would use an Assign method, but the propreties you mentioned are read-only because they are system assigned. (ActiveControl is not really a property, it is an object reference).