设置modelForm实例的初始值

Question

为什么我不能在未绑定的模型表单中设置instance = None？

def sample(request):

    prf_form = ProfileForm(instance=None)
    print prf_form.instance #debugger print
    return render_to_response(template, locals(), context_instance=RequestContext(request))

我收到以下异常：DoesNotExist

Answer 1

另一种方法是实例化一个空的Profile并传递它：

profile = Profile()
prf_form = ProfileForm(instance=profile) 

Answer 2

只是不要发送一个实例：

def sample(request):

    prf_form = ProfileForm()
    return render_to_response(template, locals(), context_instance=RequestContext(request))