I have a Winform project i want to use icon overlays like dropbox.There is Exampla at the top of what i want to achieve, when i use a function to modify a file i want to show different icon when the process is done i want to show a tick as overlay icon hopefully this made it more clear, and I used this code from :https://www.codeproject.com/Articles/545781/NET-Shell-Extensions-Shell-Icon-Overlay-Handlers
But i didn't understand how does it work ? or how should i call it. I created a class library file and use this then referenced the dll on my winform project but i can't see functions from my project because the functions are protected maybe ? (what i need to do get pass it?) and what parameters should i send to canShowOverlay function. And again i don't understand this simple code is overlaying icon where does it exactly happens ?