Automatic file numbering Form

[guido_maniglia]

Could you help me create a form and a rule for automatic numbering of parts and assemblies before saving?

I would like to create something like this:

I have no problem to creating a Form like this, but I need help with the code side

Thanks 

[youann21700]

How do you want the numbering system to work? Unique part numbers within an assembly, or unique part numbers for any new part created?

We currently have our own automatic numbering system that uses our "Parts Register" spreadsheet to determine a new number.

[guido_maniglia]

I would like a prefix for the parts/assemblies or drawing and a progressive number 

ex. ASM_001 ---> PRT_001_001

ASM_002 ---> PRT_002_001

ecc...