forms.py 文件源码

def _init_options(self):
        # sometimes self.data is a plain dict instead of a QueryDict
        data = QueryDict(mutable=True)
        data.update(self.data)
        # update available choices based on instances in self._selection
        if self._selection and hasattr(self._selection, 'lines'):
            columns = self._selection.line_columns
            self.fields['line_meta'].choices = map(table.ColumnChoice.get_field_choice, columns)
            self.fields['line_meta'].coerce = table.ColumnChoice.coerce(columns)
        # set all _meta options if no list of options was passed in
        for meta in ['study_meta', 'line_meta', 'protocol_meta', 'assay_meta', 'measure_meta']:
            if self.initial.get(meta, None) == '__all__':
                self.initial.update({
                    meta: [choice[0] for choice in self.fields[meta].choices],
                })
                # update incoming data with default initial if not already set
                if meta not in data and 'layout' not in data:
                    data.setlist(meta, self.initial.get(meta, []))
        self.data = data