To run a macro when the Open or Close event occurs, set the OnOpen or OnClose property to the name of the macro.
Remarks
You can use the CancelEvent action in an Open macro to cancel opening of the form or report. You can't use the CancelEvent action in a Close macro to cancel the Close event. However, you can use the CancelEvent action in a macro that runs when the Unload event occurs on a form. This cancels closing of the form.
If you want to refer to controls from an Open macro, you must first move the focus to the appropriate control or record. For example, to use a SetValue action in an Open macro to set the value of a control on a form, you must first use the GoToControl or GoToRecord action to access the control or the record containing the control.