如何在基于类的视图中使用url变量预填充表单？

如何解决如何在基于类的视图中使用url变量预填充表单？

我正在尝试使用在urls.py中设置的url变量自动填充django中的表单，但我不确定如何做到这一点，我尝试使用form.instance，但显然它仅适用于用户，因此这是代码，您可以查看我在说什么。

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,'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 %}

解决方法

您可以在createview上覆盖def get_initial（）并在其中添加值，以便在视图中预先填充表单。

示例

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

将此添加到视图中，并使用正确的值更新表单字段，然后返回初始值。

要从url中获取值到get_initial，请执行以下操作：

示例

    """
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 （）

，您可以访问与其一起传递的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formfield。