为模型表单额外字段指定小部件(Django) [英] Specifying widget for model form extra field (Django)

问题描述

我必须在我的模型表单中添加额外的字段.我的方法是:

I have to add extra field to my model form. My approach is:

class MyForm(forms.ModelForm):
    extra_field = forms.CharField()
    class Meta:
        model = MyModel
        widgets = {
            #Does not work
            'extra_field': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }

但似乎忽略了 class Meta 处的 extra_field 小部件定义，因为我有一个裸 input 标签而不是 模板上的 textarea.所以我应用了下一个方法:

But it seems that widget definition for extra_field at class Meta is ignored, because i have a bare input tag instead of textarea on a template. So I apply next approach:

class MyForm(forms.ModelForm):
    #It works fine
    extra_field = forms.CharField(widget=forms.Textarea())
    class Meta:
        model = MyModel

它非常适合我，但我曾经在 class Meta 声明中为表单字段指定小部件.所以我想知道:

It works perfectly for me, but I used to specify widgets for form fields at class Meta declaration. So I wonder:

为什么我的第一种方法不起作用?我做错了什么?

Why my first approach doesn't work? What I am doing wrong?

推荐答案

如果是额外的字段也没关系.这有效:

It doesn't matter if it's an extra field. This works:

class FooForm(forms.ModelForm):
    class Meta:
        model = People
        widgets = { 
            'name': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }   

这不会:

class FooForm(forms.ModelForm):
    name = forms.CharField()

    class Meta:
        model = People
        widgets = { 
            'name': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }

这是确实没有记录，这是我在可能与该行为相关的文档中找到的最好的(也许不是，这只是我能找到的最好的):

This is not documented indeed, that's the best I could find in the docs that could relate to that behaviour (maybe it doesn't, it's just the best i could find):

如果你像这样显式实例化一个表单域，Django 假设你想完全定义它的行为 [...] 你必须在声明表单域时显式设置相关参数.

此行为的实现在 django/forms/models.py 第 219 行:

The implementation of this behaviour is in django/forms/models.py line 219:

   204         if opts.model:
   205             # If a model is defined, extract form fields from it.
   206             fields = fields_for_model(opts.model, opts.fields,
   207                                       opts.exclude, opts.widgets, formfield_callback)
   208             # make sure opts.fields doesn't specify an invalid field
   209             none_model_fields = [k for k, v in fields.iteritems() if not v]
   210             missing_fields = set(none_model_fields) - 
EE 211                              set(declared_fields.keys())
   212             if missing_fields:
   213                 message = 'Unknown field(s) (%s) specified for %s'
   214                 message = message % (', '.join(missing_fields),
   215                                      opts.model.__name__)
   216                 raise FieldError(message)
   217             # Override default model fields with any custom declared ones
   218             # (plus, include all the other declared fields).
   219             fields.update(declared_fields)

在第 206 行之后，fields['name'].widget是确实是 Meta.widgets 中指定的 Textarea.

After line 206, fields['name'].widget is indeed the Textarea specified in Meta.widgets.

在第 219 行，fields 更新为声明的字段，fields['name'].widget 变成 django.forms.widgets.TextInput，这是 CharField 的默认值.

At line 219, fields is updated with declared_fields, and fields['name'].widget becomes django.forms.widgets.TextInput which is the default for CharField.

显然，明确的字段定义具有优先权.

Apparently, explicit field definitions have priority.

感谢提问，很高兴知道，好问题.

Thanks for asking, good to know, great question.

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