Directory Tree - Generates a list of subdirectories.

[Tech99]

To enumerate directories.

Use FindFirstFileEx with FindExInfoBasic and FindExSearchLimitToDirectories parameters, there is no other way to get decent performance without going to lower level API's.

Also little performance increase might be achieved using FIND_FIRST_EX_LARGE_FETCH flag, but this seems to be bit contradictory.

hSearch = FindFirstFileEx(sPath & "*", FINDEX_INFO_LEVELS.FindExInfoBasic, WFD, FINDEX_SEARCH_OPS.FindExSearchLimitToDirectories, 0&, 0&)

or 

hSearch = FindFirstFileEx(sPath & "*", FINDEX_INFO_LEVELS.FindExInfoBasic, WFD, FINDEX_SEARCH_OPS.FindExSearchLimitToDirectories, 0&, FIND_FIRST_EX_LARGE_FETCH)