ModelChoiceField ，删除空白选项 [英] ModelChoiceField , removing the blank choice

问题描述

我想摆脱-------------"选择 Django 在一个代表 ModelForm 上的外键的选择输入中添加

I want to get rid of the "-------------" choice Django adds in a select input representing a Foreign Key on a ModelForm

已经回答，您可以使用 empty_label=none 选项，但我有一个 ModelForm，而不是常规表单，并且不允许覆盖该字段.

It's been answered that you can use the empty_label=none option, but I have a ModelForm, not a regular form and overriding the field is not allowed.

我知道我可以覆盖 ModelForm 的 __init__() 方法，以便使用

I know that I can override the __init__() method of the ModelForm in order to modify a ModelChoiceField's queryset using

self.fields['my_foreign_key'].queryset = ....

但这真的很难看，因为这在主"模型上发生了超过 10 个外键，而且基于该模型的 Modelform 还不止一个

But this would be really ugly, as this happens over +10 foreign_keys on the "Main" model, and there's more than a Modelform based on this model

整个上下文:

• 这些外键中的每一个都指向同一种模型:它们是特定的选择列表，许多模型可以通过管理员轻松修改.
• 所有这些模型都通过to_field=code"关系与主模型相关，基于包含三字母代码的 Charfield(嘿，不是我的错，我不得不使用旧的 MS Access DB)，这个 CharField 有 blank=True, unique=True 选项，所以我可以为每个列表创建一个 "---No information yet---" 记录，其中有，你打赌，一个空白值而不是三个字母的代码......

• each one of these foreign_key points to the same kind of models : they are particular lists of choices, many models to ease their modification via the admin.
• all these models are related to the Main model via a "to_field=code" relation, based on a Charfield which contains a three-letter code (hey, not my fault, I had to use a legacy MS Access DB), this CharField has the blank=True, unique=True options, so I could, for each list, create a "---No information yet---" record which has, you bet, a blank value instead of a three letter code...

现在的情况是:我得到一个带有两个空白值"选项的选择输入字段:django 一个和我的，一个接一个.我也只是在这里错过了一个 'empty_label=none` 选项......

The situation is now : I get a select input field with two "blank value" choices : the django one and mine, one after the other. I just miss a 'empty_label=none` option here too...

推荐答案

如果您想删除所有 ModelChoiceField 的空白选项，您可以执行以下操作..

If you want to remove the blank choice for all ModelChoiceField you could do something like..

class Form(forms.ModelForm):
    class Meta:
        model = MyModel

    def __init__(self, *args, **kwargs):
        super(Form, self).__init__(*args, **kwargs)
        modelchoicefields = [field for field_name, field in self.fields.iteritems() if
            isinstance(field, forms.ModelChoiceField)]

        for field in modelchoicefield:
            field.empty_label = None

但那会取代所有的 ModelChoiceField ，所以也许更细粒度的东西:

But that would replace all ModelChoiceFields, so maybe something more fine grained like:

for fieldname in ('field1','field2','field3','field4','field5','field6'):
    self.fields[fieldname].empty_label = None

当然比你提到的 __init__ 覆盖更容易！

Certainly easier than the __init__ overwrite you mentioned!

您可以使用 2017+ 使用:

You can use 2017+ use:

forms.ModelChoiceField(... empty_label=None

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