Setting object event actions in Form load procedure

[Pat]

I want to programmatically define the function that runs when an event occurs
on my form. I want to program:
Sub Form_Load()
TextBox.BeforeUpdate DoMyFunction()
end

I want to do this because I don't want to have to manually assign this
function to all my fields. But when I open the form, the functions EXECUTE
rather than dynamically attach to the event procedure.

How can I assign these functions programmatically?

Thanks