fields.py 文件源码

def has_changed(self, initial, data):
        is_empty = data and (len(data) >= 2 and data[1] in [None, ''])

        if isinstance(self.widget, RelatedFieldWidgetWrapper):
            self.widget.decompress = self.widget.widget.decompress

        if is_empty and initial is None:
            # when empty data will have [u'1', u'', u''] as value
            # this will cause django to always return True because of the '1'
            # so we simply follow django's default behavior when initial is None and data is "empty"
            data = ['' for x in range(0, len(data))]
        return super(PageSelectFormField, self).has_changed(initial, data)