Change Default Value In Subform

[vix666]

I want to be able to change the default value in a subform by using code. This subform is used as a template and when the user a clicks on a button its recordsource changes, therefore i cannot just set one default on the subform control, i need to dynamically do it depending on which the user selects.
My code is shown below

Me.subfrm_area.Form.txt_area.DefaultValue = "dist_plan_adv"

Any help would be much appreciated

Thanks in advance

Vicky