I have a page that displays multiple Formsets, each of which has a prefix. The formsets are created using formset_factory the default options, including extra=1. Rows can be added or deleted with JavaScript.
If the user is adding new data, one blank row shows up. Perfect.
If the user has added data but form validation failed, in which case the formset is populated with POST data using MyFormset(data, prefix='o1-formsetname') etc., only the data that they have entered shows up. Again, perfect. (the o1 etc. are dynamically generated, each o corresponds to an "option", and each "option" may have multiple formsets).
However if the user is editing existing data, in which case the view populates the formset using MyFormset(initial=somedata, prefix='o1-formsetname') where somedata is a list of dicts of data that came from a model in the database, an extra blank row is inserted after this data. I don't want a blank row to appear unless the user explicitly adds one using the JavaScript.
Is there any simple way to prevent the formset from showing an extra row if the initial data is set? The reason I'm using initial in the third example is that if I just passed the data in using MyFormset(somedata, prefix='o1-formsetname') I'd have to do an extra step of reformatting all the data into a POSTdata style dict including prefixes for each field, for example o1-formsetname-1-price: x etc., as well as calculating the management form data, which adds a whole load of complication.
One solution could be to intercept the formset before it's sent to the template and manually remove the row, but the extra_forms attribute doesn't seem to be writeable and setting extra to 0 doesn't make any difference. I could also have the JavaScript detect this case and remove the row. However I can't help but think I'm missing something obvious since the behaviour I want is what would seem to be sensible expected behaviour to me.
Thanks.
Use the max_num keyword argument to formset_factory:
MyFormset = formset_factory([...], extra=1, max_num=1)
For more details, check out limiting the maximum number of forms.
One hitch: presumably you want to be able to process more than one blank form. This isn't too hard; just make sure that you don't use the max_num keyword argument in the POST processing side.
I've come up with a solution that works with Django 1.1. I created a subclass of BaseFormSet that overrides the total_form_count method such that, if initial forms exist, the total does not include extra forms. Bit of a hack perhaps, and maybe there's a better solution that I couldn't find, but it works.
class SensibleFormset(BaseFormSet):
def total_form_count(self):
"""Returns the total number of forms in this FormSet."""
if self.data or self.files:
return self.management_form.cleaned_data[TOTAL_FORM_COUNT]
else:
if self.initial_form_count() > 0:
total_forms = self.initial_form_count()
else:
total_forms = self.initial_form_count() + self.extra
if total_forms > self.max_num > 0:
total_forms = self.max_num
return total_forms
Related
I'm working on a small web-app that includes a filter with around 10/15 different fields,
since the user doesn't have to fill all the fields in order to be able to post the form, I implemented the below logic in order to avoid filtering the database with empty strings or values and obtain 0 results.
if not form.Price_from.data == "" and not form.Price_from.data == None:
Posts_filtered = Posts_filtered.filter(Post.Price >= form.Price_from.datas)
By doing this, I filter the column Post. Price only if the field form.Price_from field contains a value.
Since I have 10-15 fields, you can imagine that I have a lot of lines doing the same thing and I really do not like it. Since I'd like to add more fields in the future, my question is if there is a more efficient way to perform this action?
Do you think it would be faster to implement it with js? By doing that I should not need to send a post request every time and I'd save time.
Thank you!
you can use a helper function and loop through every field:
def is_filled(raw_data):
try:
value = raw_data[0]
if value == '':
return False
except (IndexError, TypeError):
return False
return True
(use raw_data from the field instead of data for this function)
you can more info here: https://stackoverflow.com/a/47450458/11699898
I have a django model form for which I allowed partial form save since its a long form. Now I want the user to come back and complete the form later.
There is one hindrance however that my database cannot accept duplicate entries with same primary key. So should I remove primary key in my database to solve this or is there another way to make it possible? Suggestions please.
Why not keep only one row per user for that form? Just add one boolean field to check whether the form is submitted or is a draft. Something like is_submitted=models.Boolean(default=False). Keep updating the row with the new values on each partial save (a separate button for Save or an AJAX call for auto save).
When the form is submitted, just mark the field is_submitted = True and perform whatever actions you want after that.
I have a formset with multiple forms:
PodFormSet = forms.inlineformset_factory(parent_model=PodP, model=Prod, form=PofModelForm, min_num=1, max_num=4,validate_min=True, extra=3)
The issues is that validate_min is not working properly:
If the user complete another form than the first one, validate_min doesn't work, say is invalid, which is not, because at least a form is completed but not the first one.
How can I override/fix this behavior ?
From what I remember (please correct me if I'm wrong) formsets in Django are not clever enough to validate against out-of-order forms. It means that
validation expects form with index (id) 0 to be present if min_num > 0 and you will have to re-format forms' indices. This is usually done on the front-end.
I need a Django Form Field which will take a list of strings.
I'll iterate over this list and create a new model object for each string.
I can't do a Model Multiple Choice Field, because the model objects aren't created until after form submission, and I can't do a Multiple Choice Field, because I need to accept arbitrary strings, not just a series of pre-defined options.
Anyone know how to do this?
Just use a regular text field delimited by commas. After you handle the form submission in the view do a comma string split based on that field. Then iterate over each one creating and saving a new model. Shouldn't be too hard.
In my case to process list of strings I used forms.JSONField(decoder="array") in my forms.py in form class
I came up with a solution -- a little hacky but it works for now.
After grabbing the form data, I stash the list in a variable:
event_locations = form_data.get('event_locations', None)
Then I remove it from form_data, so the Django Form never gets the list:
if event_locations:
del form_data['event_locations']
I instantiate my form with form_data, and handle the list separately:
f = NewEventForm(form_data)
...
for loc in event_locations:
#create new models here
I realize this doesn't directly solve the question I asked, because we still don't have a Django Form Field taking a list, but it's a way to pass in a list to a view that takes a form and be able to handle it.
All the answers I've seen to this so far have confused me.
I've made a form that gets built dynamically depending on a parameter passed in, and questions stored in the database. This all works fine (note: it's not a ModelForm, just a Form).
Now I'm trying to save the user's responses. How can I iterate over their submitted data so I can save it?
The MultipleChoiceFields are confusing me especially. I'm defining them as:
self.fields['question_' + str(question.id)] = forms.MultipleChoiceField(
label=mark_safe(required_tag +
question.label + "<br/>Choose any of the following answers"),
help_text=question.description,
required=question.required,
choices=choices,
widget=widgets.CheckboxSelectMultiple())
When I select several options, the actual posted data is something like:
question_1=5&question_1=6
Will django automatically realise that these are both options on the same form and let me access an iterable somewhere? I was going to do something like:
for field in self.cleaned_data:
print field # save the user's response somehow
but this doesn't work since this will only return question_1 once, even though there were two submitted values.
Answer: The for loop now works as expected if I loop through self.fields instead of self.cleaned_data:
for field in self.fields:
print self.cleaned_data[field]
... this doesn't work ...
Are you sure? Have you tested it? Normally the cleaned_data value for a MultipleChoiceField is a list of the values chosen on the form.
So yes, it only returns question_1 once, but that returned value itself contains multiple values.