如何在 Django 中替换一个模型对象的一个​​字段？

Question

我正在尝试更改对象的标签。 我首先过滤我正在寻找的对象，现在我不知道如何替换字段（用户标签）。

def change_tags(request, pk):
    file = Uploaded.objects.filter(pk=pk).values('usertags')
    # file = get_object_or_404(Uploaded, pk=pk)
    if request.method == "POST":
        form = ChangeTagsForm(request.POST)
        if form.is_valid():
            print(file)
            form.save()
            return HttpResponseRedirect(reverse('index'))
    else:
        form = CommentForm()
    return render(request, 'index.html', {'form': form})

class ChangeTagsForm(forms.ModelForm):
    class Meta:
        model = Uploaded
        fields = ['usertags']

Answer 1

要使用ModelForm更改对象的值，您需要为此ModelForm提供instance参数

def change_tags(request, pk):
    file = get_object_or_404(Uploaded, pk=pk)
    if request.method == "POST":
        form = ChangeTagsForm(request.POST, instance=file)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('index'))
    else:
        form = ChangeTagsForm(instance=file)
    return render(request, 'index.html', {'form': form})