python - 赋值前引用的局部变量 'context_dict'

Question

有人可以解释一下这个错误是什么意思吗？什么是作业？ context_dict 应该在哪里？或者我犯了其他错误？我是 Django 新手。非常感谢。

def add_page(request, category_name_slug):
    try:
        cat = Category.objects.get(slug=category_name_slug)
    except Category.DoesNotExist:
        cat = None

    if request.method == 'POST':
        form = PageForm(request.POST)
        if form.is_valid():
            if cat:
                page = form.save(commit=False)
                page.category = cat
                page.views = 0
                page.save()
                # probably better to use a redirect here.
                return category(request, category_name_slug)
           else:
               print form.errors
        else:
            form = PageForm()

        context_dict = {'form':form, 'category': cat}

    return render(request, 'rango/add_page.html', context_dict)

我收到此错误:

local variable 'context_dict' referenced before assignment

异常是通过 return render(reqyest, 'rango/add_page.html', context_dict) 指示我在线

相同的回溯

Answer 1

我再次重构了我的代码，这种方式有效。我的 context_dict 现在位于 if 外部语句之外，否则: form = PageForm() 位于外部 if 语句中，而不是像以前那样位于内部 if 语句中。谢谢你们帮助我。

def add_page(request, category_name_slug):
    try:
        cat = Category.objects.get(slug=category_name_slug)
    except Category.DoesNotExist:
        cat = None

    if request.method == 'POST':
        form = PageForm(request.POST)
        if form.is_valid():
            if cat:
                page = form.save(commit=False)
                page.category = cat
                page.views = 0
                page.save()
                # probably better to use a redirect here.
                return category(request, category_name_slug)
            else:
                print form.errors
    else:
        form = PageForm()

    context_dict = {'category': cat, 'form': form}

    return render(request, 'rango/add_page.html', context_dict)