How to add multiple lines of the Formset? - django

Question

i work on the form for users.
They have to add many model objects in the appropriate form.
one line is displayed when entering the GET method,
they will type in input name = "add-rows-number" the number should be displayed the number of forms in the formset
I tried with formset and with model formsetfactory
class AddCostCenters(View):
def __init__(self, *args, **kwargs):
super(AddCostCenters, self).__init__(*args, **kwargs)
self.FormSet = modelformset_factory(CostCenter, form=CostCenterAddForm, extra=self.get_form_size)
def get_form_size(self, request):
extra_rows_num = 1
if 'add-rows' in request.POST:
extra_rows_num += int(request.POST.get('add-rows-number'))
return extra_rows_num
def get(self, request, proceeding_id):
costcenter_model = CostCenter.objects.filter(
participation__provider__user=request.user,
participation__proceeding=proceeding_id
)
return TemplateResponse(request, 'costcenteradd.html', context)
def post(self, request, proceeding_id):
costcenter_model = CostCenter.objects.filter(
participation__provider__user=request.user,
participation__proceeding=proceeding_id
)
# if 'add-rows' in request.POST:
# try:
# rows_to_show = int(request.POST.get('add-rows-number'))
# except ValueError:
# rows_to_show = 0
# self.extra_rows_number += rows_to_show
if 'save_form' in request.POST:
new_cost_centers = []
post_formset_data = self.FormSet(request.POST)
if post_formset_data.is_valid():
instances = post_formset_data.save(commit=False)
new_cost_centers.append(instance)
# do something
else:
post_form = post_formset_data
context = {
'form': post_form,
}
return render(request, 'costcenteradd.html', context)
form
class CostCenterAddForm(forms.ModelForm):
# helper = CostCenterAddFormSetHelper()
def __init__(self, *args, **kwargs):
super(CostCenterAddForm, self).__init__(*args, **kwargs)
self.helper = FormHelper()
self.helper.form_show_labels = False
for field_name, field in self.fields.items():
field.help_text = None
class Meta:
model = CostCenter
fields = (
'id',
'cost_center_account_no',
'cost_center_account_name',
'departmental_code',
'values_for_year',
'only_total_cost_of_cost_center',
)
exclude = (
'participation',
'to_check',
'is_checked',
'accepted',
'use_in_calculations',
)
html
<div class="container-fluid ">
<form method="post">
{% csrf_token %}
{{ form.management_form }}
<div class="row sticky-top text-center form-nav">
<div class="col-md-2 content_center"> Numer Konta OPK </div>
<div class="col-md-4 content_center"> Nazwa konta OPK </div>
<div class="col-md-2 content_center"> Kod resortowy </div>
<div class="col-md-1 content_center"> Rok za który jest postępowanie </div>
<div class="col-md-1 content_center"> Uproszczone dane finansowe </div>
<div class="col-md-2 content_center"> Usuń </div>
</div>
<div class="section sticky-top my-2 form-panel ">
<div class="row sticky-top my-2">
<div class="col-md-2">
<button class="btn btn-success btn-block" type="submit" name="save_form">Zapisz</button>
</div>
<div class="col-md-4">
<div class="input-group mb-3">
<input class="form-control" min="1" type="number" name="add-rows-number"
value={{form.total_form_count }}
placeholder="number" aria-label="add form rows ">
<div class="input-group-append">
<button class="btn btn-info" type="submit" name="add-rows">show_rows</button>
</div>
</div>
</div>
</div>
</div>
<hr>
{% for field in form %}
<div class="row text-center">
<div class="col-md-2 paste-in">
{{field.cost_center_account_no | as_crispy_field}}
</div>
<div class="col-md-4 paste-in">
{{field.cost_center_account_name | as_crispy_field}}
</div>
<div class="col-md-2 paste-in">
{{field.departmental_code | as_crispy_field}}
</div>
<div class="col-md-1 paste-in">
{{field.values_for_year | as_crispy_field}}
</div>
<div class="col-md-1">
{{field.only_total_cost_of_cost_center | as_crispy_field}}
</div>
<div class="col-md-2">
<input type="submit" name="del_btn{{ field.instance.id }}" value="del"
{% if field.instance.id == None %}
class="btn btn-outline-secondary" disabled
{% else %}
class="btn btn-outline-danger"
{% endif%} />
</div>
</div>

Answer 1

You need to create the formset in both your get() and post() methods and add it to your context. You use the queryset attribute to populate it with existing instances:
formset = self.FormSet(queryset=CostCenter.objects.filter(...))
# or
formset = self.FormSet(queryset=CostCenter.objects.filter(...), data=request.POST)
Then in your template, you loop through your formset (what you call form in your template is actually a formset):
{{ formset.management_form }}
{% for form in formset %}
{{ form.cost_center_account_no|as_crispy_field }}
...
{% endfor %}
In your definition of self.FormSet, set extra=1 so users have at least one extra row. Remove the calculation, because that cannot work. request isn't available in the __init__() of a View (it gets added with as_view()).
Now I would not have users submit the number of extra rows, you can just deduct it from the input data. Write some javascript to let users add rows themselves directly, like you see in the admin:
Add a + button to add an extra row
The javascript clones the previous row, adds it to the list of forms (with empty input fields)
The javascript also updates the value for TOTAL_FORMS and MAX_FORMS input fields (hidden fields in the management form)
This way when users submit the formset, it will have the extra rows.