Understanding object parent child links (1 Viewer)

Hi All,
I have a subform within a form - which I've added a calculated control (text box)
It is simply the formula avg([UnitPrice]). I've named this control "UpAverage"
But the subform is in datasheet view and displays the average prices in every row.
So I've made this control invisible.

Then in the main form I've added another control (text box) which points to that control within the subform. This now being in the main form it only displays one average value for all records in the subform.

This works great but I'm trying to understand the syntax used in the link which is either a period or an exclamation point.

The link looks like this: [frm_Subform].Form![UpAverage]

This works great - and I understand the exclamation point is a parent child link.
But I don't understand why the need for the .Form after the [frm_Subform]?

Thanks in advance

Hi. The [frm_Subform] part is a control, which happens to be a subform control (as opposed to a Textbox or Combobox or Command Button control). As such, a subform control has a Form property, which refers to the Source Object you assigned to this subform control. So, to access a Textbox within this Source Object form, you'll need to use the Form property of the control. Hope it makes sense...

By way of an explanation further to DB Guys excellent explanation, I draw your attention to my website where I explain sub-forms in YouTube videos...

http://www.niftyaccess.com/control-records-displayed-subform/

Here:- Northwind - Customer Products List - Nifty Access


A many-to-many relationship can be best shown in MS Access as two subforms one showing one side of the relationship and one showing the other. These videos also demonstrate the features of subforms.

Thanks DBguy!
I got it.


And Uncle Gizmo - love your web-site! :-]

Hi. You're welcome. Uncle and I were happy to assist. Cheers!