Django-如何为模型的外键制作表格？ [英] Django - How to make a form for a model's foreign keys?

问题描述

这就是我想要做的。我想知道是否有人可以建议一个好的方法：

Here's what I'm trying to do. I'm wondering if someone can suggest a good approach:

models.py：

models.py:

class Color(models.Model):
    name = models.CharField(...

class Speed(models.Model):
    name = models.CharField(...

class Dog(models.Model):
    name = models.CharField(...
    color = models.ForeignKey(Color...
    speed = models.ForeignKey(Speed...

class DogRequest(models.Model):
    dog = models.ForeignKey(Dog...
    request_time = models.DateTimeField()

现在我想要一个页面，用户可以在其中输入或编辑DogRequest，但是表格应如下所示：

Now I want to have a page where a user can enter or edit a DogRequest, but the form should look like this:

Enter Dog Request:
---------------------
color (dropdown V)
speed (dropdown V)
|save|

那么我将如何设计视图中的表单呢？问题是用户将输入狗的属性，而不是狗的属性，因此我需要查找或创建

So how would I design that form in the view? The problem is the user will be entering properties of a dog, but not a dog. So I need to find or create a dog record depending on what the user enters.

到目前为止，我已经尝试过类似的操作：

So far I've tried something like this:

class DogRequestForm(ModelForm):
    class Meta:
        model = DogRequest
        fields = ('request_time','color','speed')
    color = forms.ModelChoiceField(queryset=Color.objects.all())
    speed = forms.ModelChoiceField(queryset=Speed.objects.all())

现在假设即使可以正常工作，我还要根据输入的颜色和速度在哪里放置代码以找出要使用（或创建）的Dog记录？以及如何从DogRequest中填写表格？

Now assuming that even works, where do I put the code to figure out the Dog record to use (or create) depending on what's entered for color and speed? And how do I fill the form from a DogRequest?

推荐答案

我认为您不想在这里使用ModelForm。没有黑客就永远不会有效，因为在调用 is_valid（）之前不会找到或创建狗对象。

I don't think you want to use a ModelForm here. It will never be valid without some hackery, since you won't have found or created the dog object before calling is_valid().

相反，我只是使用常规形式，然后覆盖DogRequest的save方法来查找或创建狗。

Instead, I'd just use a regular form, and then override the save method of DogRequest to find or create the dog.

更新：针对评论中的后续问题，我尚未对此进行测试，但类似的东西应该可以工作。

Update: Responding to the followup question in the comment, I haven't tested this, but something like it should work.

class DogRequestForm(forms.Form):
    id = forms.IntegerField(required=False, widget=forms.HiddenInput())
    color = forms.ModelChoiceField(queryset=Color.objects.all())
    speed = forms.ModelChoiceField(queryset=Speed.objects.all())

然后为您的编辑视图创建此表单的实例时，您需要使用以下实例化它：

and then when you create an instance of this form for your edit view you need to instantiate it with something like this:

data = {
    'id': dog_request_id,
    'color': dog_color,
    'speed': dog_speed,
}
form = DogRequestForm(data)

在其中填充当前 dog_request_id ， dog_color 和 dog_speed 从现有的 DogRequest 对象

where you populate the current dog_request_id, dog_color and dog_speed from your existing DogRequest object.

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