calculation to a subform from two dynamic subform

[ozzy]

Hello,
I am quite new in access so forgive me if i dont use proper terminology.
As you can see in the photo i made three subform first two of them are linked to comboboxes, with which you can choose product and the details of product show up in the subforum below.

My aim is to show the difference between some of product details (numerical ones) on the third form. (well maybe they all must be query :S )
Anyway, i dont know how to get data from first two subform and to make the calculation in the third subform since the first two subform are changable depending on the product chosen.

thank you very much...

Ozzy

[ranman256]

In each text box you can use the 'BUILDER' to pick form existing forms..
It may end up looking something like: txtBox3.ControlSource = Me.[Child1].Form![txtWidth]- Me.[Child2].Form![txtWidth]

the main form (me)
[child1] is the object name of the sub-form.
and inside that subform (.FORM)
is the txtbox (txtWidth)

[ozzy]

Hi Ranman,
Thank you for your immediate reply.
I tried a couple of version but couldnt make it, here i attached a bit more detail, would be so nice if you can have a look.
this is only i can come up with :
=[Width].[ControlSource]=[FrmComparisionDiff].[FormComparisionPage1]![Width]-[FrmComparisionDiff].[FormComparisionPage2]![Width]
I put this in 'property sheet' at 'control source' section of the textbox.


form name: FrmComparisionDiff
Subform Names; frmComparisionPage1, 2, 3
Text box names all are Width

I Dont know if its necessery to know but FrmComparisionDiff works under a navigation form called Form_SubMain

[June7]

The left part (=[Width].[ControlSource]) should be excluded from expression.

=[FrmComparisionDiff].[FormComparisionPage1]![Width]-[FrmComparisionDiff].[FormComparisionPage2]![Width]

[ozzy]

Hey June, thanks, i did, but doesnt work,
can it be because of combo boxes? because subforms are empty till i pick one of product from comboboxes.
may be i should put a button to update third subform or an event like afterupdate??

[June7]

The expression should automatically refresh when the forms populate.

What is the exact error now?

You said this is on a navigation form but the image does not look like navigation form.

If you want to provide db for analysis, follow instructions at bottom of my post.

[ozzy]

just cancel login window and open FrmComparisionDiff

the path Main_Panel> click "Product" (From_Submain) > click "Comparision" (FrmComparisionDiff)

[June7]

Are you aware of the misspelling of Comparison in the form names?

The expression should reference name of the subform container control, not the form it holds.

The following does not show error but also does not show calc until I click Refresh from the ribbon.

=[Parent].[ReportFormComparision1]![Width]-[Parent].[ReportFormComparision2]![Width]

So I was wrong about the automatic calc of the subform and therefore include code in combobox AfterUpdate event to refresh the subform.

[ozzy]

Thanx for all