Not quite sure what you are trying to do, but maybe this will help.
When you are setting a filter, you are picking a FIELD in the form record source to limit records.
It looks like the field "ConstID" is the PK field for the table. If so, then setting a filter using "ConstID" will return one record.
Here is an example for filtering on "ConstID":
(assuming "ConstID" is a number type field)
Code:
Me.Filter = ""
Me.FilterOn = False
Me.Filter = "ConstID = " & Me.ConstCmb '(usually, the first field is the bound field, so the ".Column(0)" is not needed)
Me.FilterOn = True
Here is an example for filtering on "Constructor":
(assuming "Constructor" is a text type field)
Code:
Me.Filter = ""
Me.FilterOn = False
Me.Filter = "Constructor = '" & Me.ConstructorCmb.Column(1) & "'" '(brackets not needed - you are referring to a control on a form, not a field)
Me.FilterOn = True