neutron_file_dialog.py

import Neutron

win = Neutron.Window("Example")

HeaderObject = Neutron.elements.Header(win, id="title", content="File Upload")
OPEN_DIALOG = 30

def open_file_dialog():
    path = ''.join(
        win.webview.create_file_dialog(
            OPEN_DIALOG,
            allow_multiple = True,
            file_types = ('All Files (*.*)', )
        )
    )
    print(path)
    return path

Neutron.elements.Button(win, id="submit", content="Upload File", onclick=Neutron.event(open_file_dialog))

win.show()