如何在基于类的视图中使用 url 变量预填充表单？

Question

我正在尝试使用我在 urls.py 中设置的 url 变量在 django 中自动填充表单，但我不太确定如何做到这一点，我尝试使用 form.instance 但显然它只适用于用户，所以这里是代码，所以你可以看看我在说什么。

views.py

class AddPostView(CreateView):
    model = Post
    form_class = PostForm
    template_name = 'app1/createpost.html'
    

    def form_valid(self, form, sym):
        form.instance.author = self.request.user
        form.instance.stock = self.request.sym
        return super().form_valid(form)

models.py

class Post(models.Model):
    title = models.CharField(max_length= 255)
    header_image = models.ImageField(null = True, blank = True, upload_to = 'images/')
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    body = RichTextField(blank = True, null = True)
    #body = models.TextField()
    post_date = models.DateField(auto_now_add=True)
    category = models.CharField(max_length=255, default='coding')
    snippet = models.CharField(max_length=255)
    likes = models.ManyToManyField(User, related_name = 'blog_posts')
    stock = models.ForeignKey(StockNames, null=True, on_delete = models.CASCADE)

    def total_likes(self):
        return self.likes.count()

    def __str__(self):
        return self.title + ' | ' + str(self.author)
    
    def get_absolute_url(self):
        return reverse('app1:article-detail', args=(self.id,))

class StockNames(models.Model):
    name = models.CharField(max_length=255)
    symbol = models.CharField(max_length=255)

    def __str__(self):
        return self.symbol

urls.py

urlpatterns = [
    path('add_post/<str:sym>',AddPostView.as_view(), name='addpost'),

]

forms.py

class Meta:
        model = Post
        fields = ('title','category', 'body', 'snippet', 'header_image', 'stock')

        widgets = {
            'title': forms.TextInput(attrs={'class': 'form-control', 'placeholder': 'Title', 'length':'100px'}),
            #'author': forms.TextInput(attrs={'class': 'form-control', 'value': '', 'id':'elder','type': 'hidden'}),
            #'author': forms.Select(attrs={'class': 'form-control'}),
            'category': forms.Select(choices = choice_list,attrs={'class': 'form-control', 'placeholder': 'Choices'}),
            'body': forms.Textarea(attrs={'class': 'form-control'}),
            'snippet': forms.Textarea(attrs={'class': 'form-control'}),
            'stock': forms.Select(choices = choice_list,attrs={'class': 'form-control', 'placeholder': 'Choices'})
            
            
        }

模板

{% extends 'app1/base.html' %}
{% load static %}
{% block body_block %}

{% if user.is_authenticated %}
<h1>Add Blog Post</h1>
<br><br>

<div class="form-group">
<form action="" method="post" enctype = "multipart/form-data">
    {% csrf_token %}
    {{form.media}}
    {{form.as_p}}
    <button class= "btn btn-secondary">Post</button>
</form>
</div>

<script>
    var name = "{{user.id}}";
    document.getElementById("elder").value = name;

</script>
{% else %}
You need to log in

{% endif %}



{% endblock %}

Answer 1

您可以覆盖您的 createview 上的 def get_initial() 并在那里添加值，以便在视图中预填充您的表单。

例子

def get_initial(self):
    """
    Returns the initial data to use for forms on this view.
    """
    initial = super().get_initial()

    initial['my_form_field1'] = self.request.something

    return initial

将此添加到您的视图并使用正确的值更新表单的字段，然后返回初始值。

要从 url 获取值到您的 get_initial，请执行以下操作：

例子

    """
def __init__(self, **kwargs):
    Constructor. Called in the URLconf; can contain helpful extra
    keyword arguments, and other things.
    """
    # Go through keyword arguments, and either save their values to our
    # instance, or raise an error.
    self.somevalue = kwargs.get('sym')
   

通过覆盖 def init()，您可以访问与它一起传递的 urlconf 参数。因此，当您将 sym 分配给 self.somevalue 时。

self.somevalue 变为可用。然后，您可以在 get_initial() 函数中调用 self.somevalue 并将该值传递给正确的表单域。