I have an MFC SDI application in VC++6. Data is read from disk in the Doc, converted, and displayed in the View. I have implemented a CDialog, launched from an entry on the main menu, in order to permit the setting of data display options. By including the CDialog's header in the Doc, I can successfully access the member variables of the dialog in a Doc function which instantiates the dialog. Code compiles ok, dialog can be started, but when any writes to a dialog member occurs (Editbox, Listbox), I get an Assertion failure. In release mode, nothing happens. Two days of searching have not helped find what must be some simple structural error.

>>In release mode, nothing happens.
Because asserts are only shown when compiled for debug mode. The same problem exists, its just that the assert does nothing when compiled for release.

My guess is that the program has corrupted memory while reading the file or converting to the dialog.

Assertion characteristics clear, thanks.
I am using a simplified project which represents the real project: no data is read from disk, nor written to the View.