Django form as_table(), as_p() methods not working

Question

I have a simple form class with the following single field defined:

class LaunchForm(forms.Form):

    file_name = forms.FileField(required=True, label='File to import')

in my template I have:

<form action="" method="post">
    {{ form.file_name }}
    <table>
        {{ form.as_table }}
    </table>
    {% csrf_token %}
    <input type="submit" value="Submit">
</form>

The form is being invoked from the view as follows:

class Application_Launch_View(View):

    form_class = LaunchForm
    template_name = 'application_launch.html'

    def get(self, request, app_id):
        form = self.form_class(application_id=app_id)
        return render(request, self.template_name, {'form': form})

I put the variable {{ form.file_name }} into the template just to verify that the form field exists. What is appearing on the page in my browser (along with all the other stuff in the template) is:

<django.forms.fields.FileField object at 0x032A08F0> 

But the form.as_table doesn't seem to be yielding anything.

I tried issuing the following function calls immediately after instantiating the form in my view, just before invoking the render() function:

print(form.file_name) print(form.as_table())

The server log shows:

<django.forms.fields.FileField object at 0x032A08F0>

Followed by a blank space. If I remove the call to as_table(), the blank space does NOT appear. I tried substituting form.as_p() in the view, but get the same results, so it appears both methods are at least outputting a CR or CR/FL pair.

It looks like everything is working except the as_table() and as_p() methods, and I can't figure out why...

+++++++++++++++++++

In looking into this a little deeper, I noticed that another form, when referencing a Django field object on the form from within the template doesn't yield the object class description as I posted above, but the expected form field.

So I have to ask, what is the difference between the two methods below for establishing a form field, and is there a way of making the second method (within the __init__()) work?

Method 1 (this works):

class LaunchForm:

    file_name = forms.FileField(required=True,
                        label='File to import',
                        initial='Default value')

Method 2 (this isn't working):

class LaunchForm:

    def __init__(self, *args, **kwargs)

        self.file_name = forms.FileField(required=True,
                        label='File to import',
                        initial='Default value')

Solution 1

You seem to be passing the form class itself, rather than an instance of it, to the template. You should be doing something like this:

form = LaunchForm()
return render(request, 'my_template.html', {'form': form})

etc.

Edit

To add a field dynamically inside __init__, you need to assign it to the self.fields dictionary:

self.fields['file_name'] = forms.FileField(...)

Solution 2

When there is a FileField, you need to add to the form the enctype in order to send files :

<form action="" method="post" enctype="multipart/form-data">
  {% csrf_token %}
    {{ form.file_name }}
    <table>
        {{ form.as_table }}
    </table>
    <input type="submit" value="Submit">
</form>

See the documentation

Comments

[Steve Sawyer]

I probably should have included my view code - sorry. Edited to add that. Your suggestion did make me go back and verify, but yes, I'm passing an instance, not the class.

[Steve Sawyer]

You gave me a clue as to what might be wrong here, @DanielRoseman. See my addition above. –