CompuServe Messages

I have a dialog that I use when I load my files. It informs the user of where in the file it is because some of the files are big. I call the dialog after the CFileDialog returns a filename. Problem is there seems to be no code (or messages) that are called after a Dialog box is opened,painted, and just waiting. If I put the file input code in ShowWindow, the dialog does not paint in time. If I put it in OnPaint, the dialog gets painted, but buttons do not, and if an error occurs while loading the file and one moves the message box, the file input status dialog box goes to repaint itself and I GPF. Where do I attach my file read code so that the dialog automatically executes it upon loading itself and painting itself? Thanks Pat Collado