如何在Django中的ModelForm中添加外键字段？ [英] How do I add a Foreign Key Field to a ModelForm in Django?

问题描述

我想做的是显示一个允许用户使用的表单：

What I would like to do is to display a single form that lets the user:

• 输入文档标题（从文件模型）


• 从下拉列表中选择一个 user_defined_code 填入 UserDefinedCode 模型）


• 键入 unique_code （存储在代码型号）

• Enter a document title (from Document model)
• Select one of their user_defined_code choices from a drop down list (populated by the UserDefinedCode model)
• Type in a unique_code (stored in the Code model)

我不知道如何去展示一个形式的外键关系的领域。我知道在一个视图中，您可以使用document.code_set（例如）访问当前文档对象的相关对象，但我不知道如何应用此一个ModelForm。

I'm not sure how to go about displaying the fields for the foreign key relationships in a form. I know in a view you can use document.code_set (for example) to access the related objects for the current document object, but I'm not sure how to apply this to a ModelForm.

我的模型：

class UserDefinedCode(models.Model):
    name = models.CharField(max_length=8)
    owner = models.ForeignKey(User)

class Code(models.Model):
    user_defined_code = models.ForeignKey(UserDefinedCode)
    unique_code = models.CharField(max_length=15)

class Document(models.Model):
    title = models.CharField(blank=True, null=True, max_length=200)
    code = models.ForeignKey(Code)
    active = models.BooleanField(default=True)

我的ModelForm

My ModelForm

class DocumentForm(ModelForm):
    class Meta:
        model = Document

推荐答案

关于显示外键字段您可以使用 form.ModelChoiceField 并传递一个查询器。

In regards to displaying a foreign key field in a form you can use the forms.ModelChoiceField and pass it a queryset.

所以，forms.py：

so, forms.py:

class DocumentForm(forms.ModelForm):
    class Meta:
        model = Document

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user','')
        super(DocumentForm, self).__init__(*args, **kwargs)
        self.fields['user_defined_code']=forms.ModelChoiceField(queryset=UserDefinedCode.objects.filter(owner=user))

views.py：

def someview(request):
    if request.method=='post':
        form=DocumentForm(request.POST, user=request.user)
        if form.is_valid():
            selected_user_defined_code = form.cleaned_data.get('user_defined_code')
            #do stuff here
    else:
        form=DocumentForm(user=request.user)

    context = { 'form':form, }

    return render_to_response('sometemplate.html', context, 
        context_instance=RequestContext(request))

问题：

我知道在一个视图中，您可以使用
document.code_set（例如）到
访问
当前文档对象的相关对象，但我不是
确定如何将其应用于ModelForm。

I know in a view you can use document.code_set (for example) to access the related objects for the current document object, but I'm not sure how to apply this to a ModelForm.

实际上，您的文档对象将不会有 .code_set ，因为您的文档中定义了FK关系模型。它定义了与代码的多对一关系，这意味着每个<$ c $可以有许多文档对象c>代码对象，而不是其他方式。您的代码对象将具有 .document_set 。您可以从文档对象中执行的操作是访问哪些代码它与使用 document.code 相关。

Actually, your Document objects wouldn't have a .code_set since the FK relationship is defined in your documents model. It is defining a many to one relationship to Code, which means there can be many Document objects per Code object, not the other way around. Your Code objects would have a .document_set. What you can do from the document object is access which Code it is related to using document.code.

编辑：我认为这将做你正在寻找的。 （未经测试）

edit: I think this will do what you are looking for. (untested)

forms.py：

class DocumentForm(forms.ModelForm):
    class Meta:
        model = Document
        exclude = ('code',)

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user','')
        super(DocumentForm, self).__init__(*args, **kwargs)
        self.fields['user_defined_code']=forms.ModelChoiceField(queryset=UserDefinedCode.objects.filter(owner=user))
        self.fields['unique_code']=forms.CharField(max_length=15)

views.py：

def someview(request):
    if request.method=='post':
        form=DocumentForm(request.POST, user=request.user)
        if form.is_valid():
            uniquecode = form.cleaned_data.get('unique_code')
            user_defined_code = form.cleaned_data.get('user_defined_code')
            doc_code = Code(user_defined_code=user_defined_code, code=uniquecode)
            doc_code.save()
            doc = form.save(commit=False)
            doc.code = doc_code
            doc.save()
            return HttpResponse('success')
    else:
        form=DocumentForm(user=request.user)

    context = { 'form':form, }

    return render_to_response('sometemplate.html', context, 
        context_instance=RequestContext(request))

$ b实际上你可能希望在创建代码对象时使用get_or_create。

actually you probably want to use get_or_create when creating your Code object instead of this.

doc_code = Code(user_defined_code=user_defined_code, code=uniquecode)

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