gtk:file-dialog-open (dialog parent cancellable func)

dialog -- a gtk:file-dialog object
parent -- a gtk:window parent window
cancellable -- a g:cancellable object to cancel the operation, the argument can be nil
func -- a g:async-ready-callback function to call when the operation is complete, the argument can be nil

This function initiates a file selection operation by presenting a file chooser dialog to the user. The callback will be called when the dialog is dismissed. It should call the gtk:file-dialog-open-finish function to obtain the result.

Since 4.10