Subform filtered by related combos (1 Viewer)

[Faoineag]

Good morning everyone, I need help adding a feature to my database with which I manage, among other things, the products I sell. I have a form where I specify some details based on many-to-many relationships. I have recreated the portion of the database that concerns this phase and which I attach to you. In "frmProdotti" I indicate the Product and the subcategory to which it belongs; with a button I open another form on which I insert the "Product Types"; with another button I open another form in which I insert the specific "Material Types" of that "Product Type"; with a third button I open another form in which I insert the "Material Type" which depends on "Product Type" and "Material Types". The scheme is this: each "ProductType" can have multiple "MaterialTypes" and each "MaterialType" record can have one or more "MaterialType". These 3 buttons are used to enter data in the corresponding forms. Subsequently I would like to create in the Products frm a subform smRiepilogoTipi in which I have two combined boxes: "Types of Materials" and "Type of Materials" in which I choose the values that interest me by selecting them from the forms in which I previously inserted them. Practically these two values "TipiMateriali" and "TipoMateriale" of the smRiepilogoTipi become two filters with which to filter the products: that is, I would like to have in the lower part of the frmProdotti a sub-form in which all the products with the same "Product Type" that have the specified characteristics appear from the "TipiMateriali" "TipoMateriale" combos. And here I have no idea how to do it and I would be very grateful if you would give me a suggestion. Unfortunately there is a problem: when I recreate the db to attach to it in the smRiepilogoTipi subform I get an error that I can't resolve, while this error doesn't exist in my original db. Thanks to anyone who wants to help me.