I've just uploaded the code of a fully-featured collapsible outliner which I originally developed for my own use but I’ve now decided to make publicly available. This lets you create lists or ‘trees’ of all kinds of structure information: contacts lists, TODO lists, project plans, plot outlines (for writers), a CD or MP3 database – whatever takes your fancy.
The project contains many thousands of lines of Object Pascal code for Delphi. To download the zip file, sign up to my mailing list and I’ll send you a link. In the meantime, here’s a short video overview:
If you need a quick way to learn Delphi, you can get a copy of my book, The Little Book Of Delphi, on Amazon:
Amazon US: https://amzn.to/37ZJqHF
Amazon UK: https://amzn.to/392AJxm