Django動態API中的ChoiceFields選擇引發ValueError

Question

我找到了關於如何通過Django choicefield動態設置選擇的答案？
maersu郵政對我的問題投了高票。

get_branch()的輸出為["first_branch", "second_branch"]

django==1.11
python 3.6.0

forms.py

class FactoryPOSForm(forms.ModelForm):
    branch_name = forms.ChoiceField(choices=['aa', 'bb'])

    class Meta:
        model = FactoryPOS
        fields = [
            'branch_name',
            'dealer_name',
            'shop_name',
            'factory',
        ]

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['branch_name'].choices = get_branches()

錯誤：

File "/Users/el/.pyenv/versions/eneos-factory/lib/python3.6/site-packages/django/forms/boundfield.py", line 250, in build_widget_attrs
    if widget.use_required_attribute(self.initial) and self.field.required and self.form.use_required_attribute:
  File "/Users/el/.pyenv/versions/eneos-factory/lib/python3.6/site-packages/django/forms/widgets.py", line 690, in use_required_attribute
    return use_required_attribute and first_choice is not None and self._choice_has_empty_value(first_choice)
  File "/Users/el/.pyenv/versions/eneos-factory/lib/python3.6/site-packages/django/forms/widgets.py", line 673, in _choice_has_empty_value
    value, _ = choice
ValueError: too many values to unpack (expected 2)
[22/Apr/2017 16:47:04] ERROR [django.server:124] "GET /admin/factories_pos/factorypos/add/ HTTP/1.1" 500 445135

我在哪里想念什么？

Answer 1

從文檔中，選擇應該是

本身由恰好兩個項目（例如[[（A，B），（A，B）...]）的可迭代對象組成的可迭代對象（例如列表或元組），用作該字段的選擇。 如果提供了此選項，則默認表單窗口小部件將是具有這些選擇的選擇框，而不是標准文本字段