Python django 表单存储模型的下拉列表
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django form dropdown list of stored models
提问by toni
I am trying to create a form for a library where a user can perform 2 actions: add a new book or open the stored information of an existing one. Books have 2 fields (title and author). Every time a new book is created, it is stored at the database. Any previously created book is shown as an option at a dropdown list (only the name). I want that when a user selects an option from the dropdown list, the information of the selected book appears on screen.
我正在尝试为图书馆创建一个表单，用户可以在其中执行 2 项操作：添加新书或打开现有书籍的存储信息。书籍有 2 个字段（标题和作者）。每次创建新书时，它都会存储在数据库中。任何以前创建的书籍都显示为下拉列表中的一个选项（仅名称）。我希望当用户从下拉列表中选择一个选项时，所选书籍的信息会出现在屏幕上。
I have been trying 2 different approaches, but none of them fulfills my requirements. On one hand, following this question django form dropdown list of numbersI am able to create a dropdown list, and get the selected value at views with some code like that:
我一直在尝试两种不同的方法，但它们都不能满足我的要求。一方面，按照这个问题django form dropdown list of numbers我能够创建一个下拉列表，并使用一些类似的代码在视图中获取选定的值：
class CronForm(forms.Form):
days = forms.ChoiceField(choices=[(x, x) for x in range(1, 32)])
def manage_books(request):
d = CronForm()
if request.method == 'POST':
day = request.POST.get('days')
But I want my options to be the previously stored books at the data base, and not pre-defined values.
但我希望我的选项是以前存储在数据库中的书籍，而不是预定义的值。
An other approach I have tried is to do it from the html template. There I create the following form:
我尝试过的另一种方法是从 html 模板中进行。在那里我创建了以下表单：
<form>
{% for book in list %}
<option value="name">{{ book.name }}</option>
{% endfor %}
</form>
Where book is rendered at views from this:
在此视图中呈现书籍的位置：
l = Books.objects.all().order_by('name')
In this second case the information shown at the dropdown list is the one I want, but I don't know how to get the selected value and use it at views. Perhaps using a javascript function?
在第二种情况下，下拉列表中显示的信息是我想要的信息，但我不知道如何获取所选值并在视图中使用它。也许使用javascript函数？
So my 2 requirements are: show the correct info at the list (the stored at the DB by the user) and be able to know which one has been selected.
所以我的 2 个要求是：在列表中显示正确的信息（用户存储在数据库中）并且能够知道选择了哪一个。
采纳答案by J. Ghyllebert
You should use ModelChoiceField.
您应该使用ModelChoiceField。
class CronForm(forms.Form):
days = forms.ModelChoiceField(queryset=Books.objects.all().order_by('name'))
Then your views, it should look something like this:
然后你的观点，它应该是这样的：
def show_book(request):
form = CronForm()
if request.method == "POST":
form = CronForm(request.POST)
if form.is_valid:
#redirect to the url where you'll process the input
return HttpResponseRedirect(...) # insert reverse or url
errors = form.errors or None # form not submitted or it has errors
return render(request, 'path/to/template.html',{
'form': form,
'errors': errors,
})
To add a new book or edit one, you should use a ModelForm. Then in that view you'll check if it's a new form or not
要添加新书或编辑新书，您应该使用ModelForm。然后在该视图中，您将检查它是否是新表单
book_form = BookForm() # This will create a new book
or
或者
book = get_object_or_404(Book, pk=1)
book_form = BookForm(instance=book) # this will create a form with the data filled of book with id 1
