I am using SP2013 on premise. I have 3 lists:
- Projects
- Requirements
- Issues.
Lists 2 & 3 have been added to List 1 DispForm.aspx and a lookup column and query string filter links them so that when a Project is selected a lookup column ID connects/selects only corresponding Requirements and Issues all on the same page.
Problem is that when I select the New Item link for Lists 2 or 3 on said page the ID is not included in the url and therefore I cannot do a query string on to pre-fill the Project ID Lookup value. So I need to some how append part of the current page url ".../Lists/Project%20Details/DispForm.aspx?ID=1" (without the &source) and append to the current DispForm.aspx (without the &Rootfolder) as the &Source=".../Lists/Project%20Details/DispForm.aspx?ID=1" but can't be hardcoded, has to be able to query the ID variable from the current URL.
Any suggestions or ideas? I had a solution if I used a Document Set as the Project list but Document Sets proved to be unworkable in other areas so I am using 3 regular lists instead.