You may want to check out the sample shipped with VFP 6.0 (and possibly earlier VFP versions). You'll find it in VFP Help, under CONTENTS|SAMPLES|VISUAL FOXPRO SAMPLES...then run "Solutions Sample". Next, when the form loads, expand the 'ActiveX' node, then the 'ActiveX Controls' node and finally choose "Provide a hierarchical display of items". You can run it, then view the code.

It allows you to choose a directory, then display subdirectories...this can be your left side. Then, when user highlights a directory on left, you can fire code to display all files on right.

Good luck - Victor