Seems you are expecting the root folder. Note that the dependency injection looks at the class name, not the parameter name. So calling it $rootFolder won't magically make it an instance of root folder.
Have you tried replacing Folder with IRootFolder ?
If that doesn't work you could also simply call \OC::$server->getRootFolder() or \OC::$server->getUserFolder()
I will try your suggestions but I am not sure to understand why I can not instantiate a parameter from the Folder Class. Maybe my parameter name is not very clear but i really want to use Folder Class functions not IRootFolder Class function.
In addition when I call \OC::$server->getRootFolder() what exactly is going on ? I mean can I use every function like that ?
Not sure what you mean with "instantiating a parameter".
If you need an instance of Folder, the question is what folder. From the parameter name I guessed that you wanted the root folder. To get the root folder use \OC::$server->getRootFolder() is the quickest way.
Ok to have a precise idea of what I want to do : I would like to get one folder named "DataBase VoNZ" in my Owncloud, open it, et get the owner of each files.
I know a lot of functions exits for that, like getOwner and openDir for example . These functions belongs to the class IStorage, Folder or FileInfo.
But to use this function, I though that you need an instance of each class and after that you can use : $paremeter = this->instanceOfClass->function();
It's what I did with the class IConfig and it works very well. But when I try to call an instance of any class related to File I had the same error which appears.
I understand that I do big mistakes but I do not understand which other means I can use.
Can you just confirm that using : βto instantiate the PageController explicitly from within your Application class and do all the parameter wiring manually.β could works now that I explain a little bit more my goal ?
to access the File/Folder functions (e.g. getOwner) you need to initiate the rootfolder first because this creates the "pointer" your your files of your user.