Django MultiValueField - 如何将选择传递给 ChoiceField？

Question

我有一个带有 charfield 和 choicefield 的多值字段。我需要将选择传递给 choicefield 构造函数，但是当我尝试将其传递到自定义多值字段时，我收到错误 __init__() 获得了意外的关键字参数“choices”。

我知道代码的其余部分有效，因为当我从 __init__ 和 super 中删除choices关键字参数时，多值字段显示正确，但没有任何选择。

这就是我设置自定义多值字段的方式：

class InputAndChoice(object):
    def __init__(self, text_val='', choice_val=''):
        self.text_val=text_val
        self.choice_val=choice_val

class InputAndChoiceWidget(widgets.MultiWidget):
    def __init__(self, attrs=None):
        widget = (widgets.TextInput(),
                  widgets.Select()
                 )
        super(InputAndChoiceWidget, self).__init__(widget, attrs=attrs)

    def decompress(self,value):
        if value:
            return [value.text_val, value.choice_val]
        return [None, None]


class InputAndChoiceField(forms.MultiValueField):
    widget = InputAndChoiceWidget

    def __init__(self, required=True, widget=None, label=None, initial=None,
                 help_text=None, choices=None):
        field = (
                 fields.CharField(),
                 fields.ChoiceField(choices=choices),
                 )
        super(InputAndChoiceField, self).__init__(fields=field, widget=widget, 
              label=label, initial=initial, help_text=help_text, choices=choices)

我这样称呼它：

input_and_choice = InputAndChoiceField(choices=[(1,'first'),(2,'second')])

那么如何将选项传递到我的 ChoiceField 字段？

编辑：

我已经尝试过 stefanw 的建议，但仍然没有成功。我已经使用logging.debug在init和self.fields[1].choices末尾打印出InputAndChoiceField的内容，其中包含如上所述的正确值，但它不会在浏览器中显示任何选择。

Answer 1

我遇到了这个完全相同的问题并像这样解决了它：

class InputAndChoiceWidget(widgets.MultiWidget):
    def __init__(self,*args,**kwargs):
        myChoices = kwargs.pop("choices")
        widgets = (
            widgets.TextInput(),
            widgets.Select(choices=myChoices)
        )
        super(InputAndChoiceWidget, self).__init__(widgets,*args,**kwargs)

class InputAndChoiceField(forms.MultiValueField):
    widget = InputAndChoiceWidget

    def __init__(self,*args,**kwargs):
        # you could also use some fn to return the choices;
        # the point is, they get set dynamically 
        myChoices = kwargs.pop("choices",[("default","default choice")])
        fields = (
            fields.CharField(),
            fields.ChoiceField(choices=myChoices),
        )
        super(InputAndChoiceField,self).__init__(fields,*args,**kwargs)
        # here's where the choices get set:
        self.widget = InputAndChoiceWidget(choices=myChoices)

将“choices”kwarg 添加到小部件的构造函数中。然后在创建字段后显式调用构造函数。

Answer 2

ModelChoiceField 是从技术上讲，它是一个 ChoiceField，但它实际上并未使用 ChoiceField 的任何实现。所以，这就是我的使用方法。

class ChoiceInputMultiWidget(MultiWidget):
    """Kindly provide the choices dynamically"""
    def __init__(self, attrs=None):
        _widget = (
            Select(attrs=attrs),
            TextInput(attrs=attrs)
        )
        super().__init__(_widget, attrs)

class ModelChoiceInputField(MultiValueField):
    widget = ChoiceInputMultiWidget

    def __init__(self, *args, **kwargs):

        _fields = (
            ModelChoiceField(queryset=Type.objects.all()),
            CharField()
        )
        super().__init__(_fields, *args, **kwargs)

        # Use the auto-generated widget.choices by the ModelChoiceField
        self.widget.widgets[0].choices = self.fields[0].widget.choices

Answer 3

看看 forms.MultiValueField 的 __init__ 的来源：

def __init__(self, fields=(), *args, **kwargs):
    super(MultiValueField, self).__init__(*args, **kwargs)
    # Set 'required' to False on the individual fields, because the
    # required validation will be handled by MultiValueField, not by those
    # individual fields.
    for f in fields:
        f.required = False
    self.fields = fields

所以我会像这样覆盖 __init__ ：

def __init__(self, *args, **kwargs):
    choices = kwargs.pop("choices",[])
    super(InputAndChoiceField, self).__init__(*args, **kwargs)
    self.fields = (
        fields.CharField(),
        fields.ChoiceField(choices=choices),
    )

你甚至可能想做super(MultiValueField, self).__init__(*args, **kwargs) 而不是 super(InputAndChoiceField, self).__init__(*args, **kwargs) 因为你自己设置字段而不是通过参数获取它们。

Answer 4

传递小部件中的选择为我解决了这个问题

class InputAndChoiceWidget(widgets.MultiWidget):
    def __init__(self, attrs=None):
        choices = [('a', 1), ('b', 2)]
        widget = (widgets.TextInput(),
                  widgets.Select(choices=choices)
                 )
        super(InputAndChoiceWidget, self).__init__(widget, attrs=attrs)

Answer 5

class HTML5DateInput(DateInput):

    input_type = 'date'


class CustomSelectRangeWidget(forms.MultiWidget):

    def __init__(self, attrs=None, choices = ()):
        widgets = (Select(attrs=attrs, choices=choices), HTML5DateInput(attrs=attrs), HTML5DateInput(attrs=attrs))
        super(CustomSelectRangeWidget, self).__init__(widgets, attrs)

    def decompress(self, value):
        if value:
            return [value.field, value.start, value.stop]
        return [None, None, None]

    def format_output(self, rendered_widgets):
        return '-'.join(rendered_widgets)

class CustomSelectRangeField(forms.MultiValueField):

    widget = CustomSelectRangeWidget

    def __init__(self, *args, **kwargs):
        if kwargs.has_key('choices') :
            choices = kwargs.pop('choices')
        else:
            choices = ()
        fields = (
            forms.ChoiceField(choices=choices),  #field with choices,
                                             # so that clean can be passed
            forms.DateField(),
            forms.DateField(),
            )
        super(CustomSelectRangeField, self).__init__(fields=fields, *args, **kwargs)
        #initialize widget with choices.
        self.widget = CustomSelectRangeWidget(choices=choices)

    def compress(self, data_list):
        if data_list:
           #check if datalist has 3 not null values
           if len([v for v in data_list if v not in [None, '']]) == 3:
               out_dict = {'field':data_list[0], 'start':data_list[1], 'stop':data_list[2]}
               return out_dict
       return None