Django File Upload，无法使用实例对象中的表单添加文件字段

Question

I need to save a file upload object, but in two views... First views can save without problem, but the second i get nothing change in my object

I have a models.py

class file_upload(models.Model):

    x= models.FileField()
    y = models.FileField()

I have forms.py

class form_upload(ModelForm):
    class Meta:
        model = file_upload
        fields = ('x',)    
        widgets={
            'x': FileInput(attrs={'class': 'form-control'}),

class form_upload_2(ModelForm):
    class Meta:
        model = file_upload
        fields = ('y',)
        widgets={
             'y': FileInput(attrs={'class': 'form-control'}),

I have created an objects, also have uploaded a file on "x", i need to add file on "y" using form_upload_2

this is my views.py

data_upl_instance = file_upload.objects.get(id=1)
form = form_upload2(request.FILES,request.POST,instance=data_upl_instance)

if request.method == "POST":
    if form.is_valid():
        print(form.cleaned_data['y'])
        form.save()

mydata['form'] = form

return render(request, "status.html", mydata)

this is my status.html

<form action="" method="post" enctype="multipart/form-data" class="form-horizontal">{% csrf_token %}
           <div class="alert alert-danger">
               {{ form }}
            </div>
           <button type="submit" class="btn red">Upload</button>
            </div>
</form>

After i clicked submit, the result is

• Printed "None" on terminal
• Form is valid but nothing change, file cant be uploaded

Answer 1

Your form_upload_2 class don't have field y . Change it to

class form_upload_2(ModelForm):
    class Meta:
        model = file_upload
        fields = ('y',)
        widgets={
         'y': FileInput(attrs={'class': 'form-control'}),

Also follow naming conventions while naming a class. file_upload is not a good class name. Use FileUpload . https://www.python.org/dev/peps/pep-0008/#class-names

Also your form, please try to change like this

if request.method == "POST":
    form = form_upload2(request.FILES,request.POST,instance=data_upl_instance)
    if form.is_valid():
        print(form.cleaned_data['y'])
        form.save()
else:
    form = form_upload2(instance=data_upl_instance)


mydata['form'] = form

return render(request, "status.html", mydata)

Answer 2

Finally solve the problem, the problem is i have nothing in request.POST , i just need request.FILES .. so i change "request.POST" to "request.POST or None"

this is my new views.py

data_upl_instance = file_upload.objects.get(id=1)
form = form_upload2(instance=data_upl_instance)

if request.method == "POST":
    form = form_upload2(request.FILES,request.POST or None,instance=data_upl_instance)
    if form.is_valid():
        print(form.cleaned_data['y'])
        form.save()

mydata['form'] = form

return render(request, "status.html", mydata)