Delphi and COM: TLB and maintenance issues

Question

In the company that i work, we develop all the GUI in C#, but the application kernel is mainly developed in Delphi 5 (for historical reasons), with a lot of components made

Answer 1

We have also just installed Delphi 2009 and it does seem to have improved the support for Typelibraries. However I have worked with COM and type libraries for quite some time and here are my general gotchas that I have found over the years. I would agree its pretty buggy and is all the way up to Delphi 2006 (our version prior to using 2009).

• Always have every file writeable before opening. This may sound obvious, but when working with source control sometimes we forget to do this and try to remove readonly flag after opening a file - Delphi cant deal with this. Ensure tlb is writable before opening.
• If editing a standalone typelibrary you MUST have a project open. For some reason if you open a type library on its own it will not save. Create a blank project and then open your typelibrary. For some reason this allows the type library to be saved.
• If your type library is used by an application or COM+ ensure that application is shut down or COM+ disabled before opening the type library. Any open apps will prevent the type library from being saved.

However I think your best solution is probably an upgrade. You get Unicode support too.