How deeply get all controls gaind from FindWindowEx

please take a look at this link :

get all controls by FindWindowEx -> refer to second answer

there is an opened application outside of my windows form application and using with spy++ i found my goal window's handle.

there are many controls inside that window (not windows)(ex, button-textBox checkBox-etc)

how can i loop in all these controls and access their properties?

spy++ for a reason can not show inside controls, i don't know why!

i test some alternatives of c++ (windows defective & etc), but none of them can show me inside controls!

please after giving me an answer to my question let me know about that spy++ issue!

Thanks In Advance