Modify MDI app using CHtmlView child to add splitter?

I have a large MDI app which uses CHtmlView-derived child windows.

I'd like to change to a splitter-type child window, still using a CHtmlView for the right pane.

How can I convert this existing app?

In my oppinion, "modifying" an existing application, that is, somehow hacking the source files, will result in a monumental mess. If I were you, I'd start a new project and reuse the view and document classes.

Basically, in your current code, you have a CFrameWnd derived window hosting a CHtmlVeiw derived view. What you need is to have the frame host a CSplitterWnd window, which will host the view(s). Create a new, blank application, and have the wizard add splitters to your windows. Then, have a look at the generated code, and mimic it in your project.