To do this, you'd need a relationship that links the Product Name field in Line Items to the Product Name (or description, you'd have to check the table for the precise name) field in Products.
Companies do change the names or descriptions of their products and you don't want such a change to adversely affect the function of your database. That's why the starter solution uses the Product ID code with a two column value list that also lists the product names in the first place.
There are search tools you can devise that allow you to enter part of a name or description and then you can select from the list of matching products to add it to the invoice. A script enters the Product ID number into the next row of your portal when you select the product by clicking it or a button next to it.
That was the first thing I did when tried to modify the starter solution. I linked the Products::Product Name field to the Line Items::Product Name but nothing is shown on the Product Name edit box in the invoices portal when I write in.
I assume I'll need to add a script to find the Product ID of the Product Name on the portal edit box triggered by the event OnObjectExit, but I don't have idea about how that script should be.
Please, could you take a look to the Invoices starter solution and tell me what should do I do? I know I'm asking a lot, but I have no idea and I'm totally lost.
Anyway, thank you very much.
Setting up the relationship, remember that I said this was not a good idea, is just the first step. To get the drop down of product names requires that you create a value list of the names and format the field to use it.
Here's one scripted approach that you can try to adapt to this purpose: Tutorial: How to use an auto-complete drop down list when selecting records related by ID number
You might also download the Known Bugs List file (click the blue download button) and look at the portal in the window that pops up when you click New or Edit on the first layout. There's a portal field with a drop down, auto-complete enabled list used to look up bug reports by name, but then the triggered script enters the BugID number to keep the relationship. The issue with this is that the names used may change in the future. This is an issue I judged minor for bug reports, but could create more serious issues with an invoicing system.
With these scripted methods, you should not change the relationship as it remains based on the ID number.
I already know your autocomplete drop down tutorial, before asking I did a search. I was trying to implement with my database but I wasn't able to do it work.
Anyway I think your known Bugs List database may help me. I don't understand everything but does all I want to do. Let's see if I can implement into the starter solution.
The bug list file and the tutorial implement much the same approach here. Feel free to focus in on specific areas where it didn't work for you.