用于模型形式的raw_id_fields [英] raw_id_fields for modelforms

问题描述

我有一个模型表单，其中有一个字段，该字段是模型的40,000行的ForeignKey值。默认的模型形式试图创建一个具有40,000个选项的选择框，至少可以说这不是理想的选择。

I have a modelform which has one field that is a ForeignKey value to a model which as 40,000 rows. The default modelform tries to create a select box with 40,000 options, which, to say the least is not ideal. Even more so when this modelform is used in a formset factory!

在管理员中，使用 raw_id_fields ，但似乎没有等效的模型形式。我该怎么做？

In the admin, this is easiely avoidable by using "raw_id_fields", but there doesn't seem to be a modelform equivalent. How can I do this?

这是我的模型形式：

class OpBaseForm(ModelForm):

    base = forms.CharField()

    class Meta:
        model = OpBase
        exclude = ['operation', 'routes']
        extra = 0
        raw_id_fields = ('base', )   #does nothing

第一行粗体字通过不创建庞大笨拙的选择框而起作用，但是当我尝试保存这种形式的字段集时，出现错误： OpBase.base必须是 Base实例。为了保存模型表单， base必须是Base实例。显然，基本主键的字符串表示形式还不够（至少不是自动）。我需要某种机制将表单中提供的字符串更改为Base实例。而且这种机制必须在表单集中起作用。有任何想法吗？如果仅 raw_id_fields 可以工作，这将很容易。但据我所知，它仅在管理员中可用。

The first bolded line works by not creating the huge unwieldy selectbox, but when I try to save a fieldset of this form, I get the error: "OpBase.base" must be a "Base" instance. In order for the modelform to be saved, 'base' needs to be a Base instance. Apparently, a string representation of a Base primary key isn't enough (at least not automatically). I need some kind of mechanism to change the string that is given my the form, to a Base instance. And this mechanism has to work in a formset. Any ideas? If only raw_id_fields would work, this would be easy as cake. But as far as I can tell, it only is available in the admin.

推荐答案

您需要更改 widget 表示 base 字段，而不是字段类型。我认为这会起作用：

You need to change the widget for the base field, not the field type. I think this would work:

class OpBaseForm(ModelForm):
    base = forms.ModelChoiceField(queryset=Base.objects.all(), 
                                  widget=forms.TextInput)

    class Meta:
        model = OpBase
        ... etc... 

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