Django set initial pre-filled field value

Question

I have two models:

class Budget(models.Model):
    name = models.CharField(max_length=25)
    quantity = models.DecimalField(max_digits=10, decimal_places=2)
    date = models.DateField(default=now)
    datecompleted = models.DateTimeField(blank=True, null=True)

    class Meta:
        ordering = ['-date']

    def __str__(self):
        return self.name

class Expenses(models.Model):
    name = models.CharField(max_length=25)
    quantity = models.DecimalField(max_digits=10, decimal_places=2)
    budget = models.ForeignKey(Budget, on_delete=models.CASCADE,
                               related_name='budget_expense')
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    date = models.DateField(default=now)

    def __str__(self):
        return self.name

    class Meta:
        ordering = ['-date']

and my Form as follow

class ExpenseForm(forms.ModelForm):
    date = forms.DateTimeField(
        widget=forms.widgets.DateTimeInput(attrs={'class': 'form-control', 'type': 'datetime-local'}),
        label='Data', input_formats=['%d/%m/%Y %H:%M'])

    class Meta:
        model = Expenses
        fields = ('name', 'quantity', 'budget', 'category', 'date')

and now I trying to create an instance of Expense with pre-filled (existing) Budget instance with below code:

def expense_add(request, budget_id=None):
    if request.method == 'GET':
        budget = get_object_or_404(Budget, pk=budget_id)
        form = ExpenseForm(initial={'budget': budget})
        return render(request, 'budget/expense-create.html', {'form': form})
    else:
        form = ExpenseForm(request.POST or None)
        if form.is_valid():
            form.save()
            return redirect('list')
        return render(request, 'budget/expense-create.html', {'form': form})

url pattern:

    path('budget/<int:budget_id>/expense-create', views.expense_add, name='expense-create-new'),
    path('budget/expense-create', views.expense_add, name='expense-create-new'),

but, as you may guess there is nothing in budget field inside my formfield.

P.S. budgetdetail.view:

def budget_detail(request, pk):
    instance = get_object_or_404(Budget, pk=pk)
    expenses_list = Expenses.objects.filter(budget_id=instance.pk)
    budget_id = instance.pk
    return render(request, 'budget/budget-detail.html',
                  {'instance': instance, 'expenses_list': expenses_list})

Please help. Thank you all!

Does this answer your question? [foreign key as initial value not passed to the ModelForm in django](https://stackoverflow.com/questions/35226793/foreign-key-as-initial-value-not-passed-to-the-modelform-in-django) — Ankit Tiwari, May 20 '22 at 12:35
Thanks! Yeah, it's a similar issue and I tried to replace (initial={'budget': budget.name}) to (request.POST or None, initial={'budget': budget,}) but result same - empty field — Ches_Ter, May 20 '22 at 12:54
Hello @Ches_Ter can you share updated code by making an [edit] — Ankit Tiwari, May 20 '22 at 18:01
Hello @Ches_Ter you're passing `request.POST ` inside youe `request.method == "GET"` try to pass like this `ExpenseForm(initial={'budget': budget})` — Ankit Tiwari, May 20 '22 at 18:39
Hello @Ches_Ter try to print budget and check that it contain any values. — Ankit Tiwari, May 20 '22 at 18:50
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/244915/discussion-between-ches-ter-and-ankit-tiwari). — Ches_Ter, May 20 '22 at 19:00
Hello @Ches_Ter if it's empty then your initial values will be empty and your form will render empty data — Ankit Tiwari, May 20 '22 at 19:22
But what is wrong with it, why it's empty? Let me know please if you need more details — Ches_Ter, May 20 '22 at 19:31
I think you've to check for id you're passing as an argumnet don't give default value as **None** — Ankit Tiwari, May 20 '22 at 19:32

Babis Skeparnakos · Accepted Answer · 2022-05-20T12:50:12.337

1

The problem is in the views.py where you set the initial value of budget. It expects either a budget object or the id of the budget object but you give the name of the object. So you can fix it by removing the .name from the 4th line.

The corrected view:

def expense_add(request, pk):
    if request.method == 'GET':
        budget = get_object_or_404(Budget, pk=pk)
        form = ExpenseForm(initial={'budget': budget})
        return render(request, 'budget/expense-create.html', {'form': form})
    else:
        form = ExpenseForm(request.POST or None)
        if form.is_valid():
            form.save()
            return redirect('list')
        return render(request, 'budget/expense-create.html', {'form': form})

edited May 20 '22 at 12:50

answered May 20 '22 at 12:48

Babis Skeparnakos

34
1
7

Thank you. I removed it. Nothing changed. Just copied your code and pasted in to my view. Reload local server. Same empty field as result – Ches_Ter May 20 '22 at 13:07
Did you insert the id of an existing budget object in the url? – Babis Skeparnakos May 20 '22 at 13:15
Added picture with html. Did you mean that Id? – Ches_Ter May 20 '22 at 13:21
path('budget//expense-create', views.expense_add, name='expense-create-new'), But what I mentioned above is id of expense instance not budget I guess))) – Ches_Ter May 20 '22 at 13:34
1

It should be of a budget instance, since the expense doesn't exist yet and when created it will have a foreign key to a budget instance. – Babis Skeparnakos May 20 '22 at 13:40
Thanks, yeah. I think I’m beginning to understand now, but, how I can pass ... one more Id?))) – Ches_Ter May 20 '22 at 13:47
I don't understand where do you want an extra id. – Babis Skeparnakos May 20 '22 at 13:57
Sorry. I meant on a last html screen where: href="{% url 'expense-create-new' instance.pk %}" (marked red) if I change - instance.pk on something else then Exception Value I got – Ches_Ter May 20 '22 at 14:05
1

Is instance an instance of budget? Because it should be. Can you also share the budget view (that renders budget-detail.html) for more clarification? – Babis Skeparnakos May 20 '22 at 14:19
`def budget_detail(request, pk): instance = get_object_or_404(Budget, pk=pk) expenses_list = Expenses.objects.filter(budget_id=instance.pk) return render(request, 'budget/budget-detail.html', {'instance': instance, 'expenses_list': expenses_list})` – Ches_Ter May 20 '22 at 14:25

score 0 · Answer 2 · answered May 20 '22 at 20:14

0

Thank you all! In my url pattern there was another path('budget/<int:pk>/expense-create', ExpenseCreateView.as_view(), name='expense-create'), which is cover or overwrite my view or something I suppose...once i comment it def expense_add - worked!!

answered May 20 '22 at 20:14

Ches_Ter

46
8

Django set initial pre-filled field value

2 Answers2