Django形式有选择,但也有自由文本选项？

Question

我正在寻找的东西:一个小工具,为用户提供一个下拉选项列表,但后面还有一个文本输入框,供用户输入新值.

后端模型将具有一组默认选项(但不会在模型上使用choices关键字).我知道我可以(并且我已经)通过让表单同时具有ChoicesField和CharField来实现这一点,并且如果ChoicesField保留默认值,则代码使用CharField,但这感觉"un-django"就像.

是否有一种方法(使用Django-builtins或Django插件)来定义类似ChoiceEntryField(在IIRC为此进行模拟的GtkComboboxEntry之后)？

如果有人发现这一点,请注意,从UX角度来看,如何最好地完成我正在寻找的内容存在类似的问题,请访问https://ux.stackexchange.com/questions/85980/is-there-a-ux-图案换下拉优选的-丁自由文本允许的

Answer 1

我建议使用自定义Widget方法,HTML5允许您使用下拉列表进行自由文本输入,该列表可用作一个选择或写入其他类型的字段,这就是我的方法:

fields.py

from django import forms

class ListTextWidget(forms.TextInput):
    def __init__(self, data_list, name, *args, **kwargs):
        super(ListTextWidget, self).__init__(*args, **kwargs)
        self._name = name
        self._list = data_list
        self.attrs.update({'list':'list__%s' % self._name})

    def render(self, name, value, attrs=None, renderer=None):
        text_html = super(ListTextWidget, self).render(name, value, attrs=attrs)
        data_list = '<datalist id="list__%s">' % self._name
        for item in self._list:
            data_list += '<option value="%s">' % item
        data_list += '</datalist>'

        return (text_html + data_list)

forms.py

from django import forms
from myapp.fields import ListTextWidget

class FormForm(forms.Form):
   char_field_with_list = forms.CharField(required=True)

   def __init__(self, *args, **kwargs):
      _country_list = kwargs.pop('data_list', None)
      super(FormForm, self).__init__(*args, **kwargs)

    # the "name" parameter will allow you to use the same widget more than once in the same
    # form, not setting this parameter differently will cuse all inputs display the
    # same list.
       self.fields['char_field_with_list'].widget = ListTextWidget(data_list=_country_list, name='country-list')

views.py

from myapp.forms import FormForm

def country_form(request):
    # instead of hardcoding a list you could make a query of a model, as long as
    # it has a __str__() method you should be able to display it.
    country_list = ('Mexico', 'USA', 'China', 'France')
    form = FormForm(data_list=country_list)

    return render(request, 'my_app/country-form.html', {
        'form': form
    })

Answer 2

我知道我有点迟到了,但我最近使用了另一个解决方案.

我使用了带有参数的django-floppyformsInput小部件.这将生成一个HTML5 元素,您的浏览器会自动创建一个建议列表(另请参阅此SO答案).datalist<datalist>

以下是模型表单的简单外观:

class MyProjectForm(ModelForm):
    class Meta:
        model = MyProject
        fields = "__all__" 
        widgets = {
            'name': floppyforms.widgets.Input(datalist=_get_all_proj_names())
        }

Answer 3

编辑：更新以使其也适用于 UpdateView

所以我正在寻找的似乎是

工具.py：

from django.core.exceptions import ValidationError
from django import forms


class OptionalChoiceWidget(forms.MultiWidget):
    def decompress(self,value):
        #this might need to be tweaked if the name of a choice != value of a choice
        if value: #indicates we have a updating object versus new one
            if value in [x[0] for x in self.widgets[0].choices]:
                 return [value,""] # make it set the pulldown to choice
            else:
                 return ["",value] # keep pulldown to blank, set freetext
        return ["",""] # default for new object

class OptionalChoiceField(forms.MultiValueField):
    def __init__(self, choices, max_length=80, *args, **kwargs):
        """ sets the two fields as not required but will enforce that (at least) one is set in compress """
        fields = (forms.ChoiceField(choices=choices,required=False),
                  forms.CharField(required=False))
        self.widget = OptionalChoiceWidget(widgets=[f.widget for f in fields])
        super(OptionalChoiceField,self).__init__(required=False,fields=fields,*args,**kwargs)
    def compress(self,data_list):
        """ return the choicefield value if selected or charfield value (if both empty, will throw exception """
        if not data_list:
            raise ValidationError('Need to select choice or enter text for this field')
        return data_list[0] or data_list[1]

示例使用

(表单.py )

from .utils import OptionalChoiceField
from django import forms
from .models import Dummy

class DemoForm(forms.ModelForm):
    name = OptionalChoiceField(choices=(("","-----"),("1","1"),("2","2")))
    value = forms.CharField(max_length=100)
    class Meta:
        model = Dummy

（示例虚拟模型.py :)

from django.db import models
from django.core.urlresolvers import reverse

class Dummy(models.Model):
    name = models.CharField(max_length=80)
    value = models.CharField(max_length=100)
    def get_absolute_url(self):
        return reverse('dummy-detail', kwargs={'pk': self.pk})

（样品哑views.py： ）

from .forms import DemoForm
from .models import Dummy
from django.views.generic.detail import DetailView
from django.views.generic.edit import CreateView, UpdateView


class DemoCreateView(CreateView):
    form_class = DemoForm
    model = Dummy

class DemoUpdateView(UpdateView):
    form_class = DemoForm
    model = Dummy


class DemoDetailView(DetailView):
    model = Dummy