Cascading Combo Box Parameter

[L'apprentis]

I have an unbound Form with a Subform bound to a query. The query parameters are selected by the users via Unbound cboboxes. The form is working but I would like to add a feature on each cbobox that would allow to show "All" the data (ie:Show the data like if there was no parameter on that field). I can't see how to add this feature, is anybody got any idea?

 

[L'apprentis]

Thanks

Hi Gizmo,
Thanks for your code it's really helpfull, I think I managed to make it work but there is still some point that I don't totally understand, what is the function of (*) in a query.
Why do we use the SQl "LIKE" with the functions in the criteria of the SfrmQuery?
This method is working but if the function is applied on a field with Null values, all the corresponding records are not shown anymore.

 

[L'apprentis]

I am not sure my explanation is really clear, but here is a more precise example:
Tbl1
FldX
FldPipeID

Tbl2
FldPipeID
FldPipeSize

Query shows all the record from Tbl1 and the Field FldPipeSise from Tbl2
*Join property are set up to show all the record from Tbl1
*Tbl1 & tbl2 are Linked by FldPipeSize
*FldPipeID can be blank in Tbl1

When the Criteria is applied (Like fct....()) on the criteria of the Field FldPipeSize, all the record from Tbl1 with a null PipeID are not shown?