Interesting thing about File Explorer is that the 20-year-old APIs for extending it still work! While File Explorer has changed between Windows versions, the underlying Win32 API seems to be the same.
A year ago I dove into shell extensions [1] to implement a drag-and-drop gesture for a file type. I wanted to create a bookmarking system for files in File Explorer based on nothing more than the bookmark being named after the file I want to bookmark (so they're next to each other when sorted from A-Z) [2]. I had not used Visual C++ before but the tutorials I found from the early 2000s, and some helpful advice from MSFT via Stackoverflow, got me through it.
There is also a simpler way to write Shell extensions using a C# wrapper if that works for your use case [3].
A year ago I dove into shell extensions [1] to implement a drag-and-drop gesture for a file type. I wanted to create a bookmarking system for files in File Explorer based on nothing more than the bookmark being named after the file I want to bookmark (so they're next to each other when sorted from A-Z) [2]. I had not used Visual C++ before but the tutorials I found from the early 2000s, and some helpful advice from MSFT via Stackoverflow, got me through it.
There is also a simpler way to write Shell extensions using a C# wrapper if that works for your use case [3].
[1]: https://docs.microsoft.com/en-us/windows/win32/shell/shell-e... [2]: https://filemark.app/ [3]: https://github.com/dwmkerr/sharpshell