In Django forms, it can check whether the form is valid:
if form.is_valid():
return HttpResponseRedirect('/thanks/')
But I'm missing what to do if it isn't valid? How do I return the form with the error messages? I'm not seeing the "else" in any of the examples.
This question is related to
django
django-forms
You can put simply a flag variable, in this case is_successed.
def preorder_view(request, pk, template_name='preorders/preorder_form.html'):
is_successed=0
formset = PreorderHasProductsForm(request.POST)
client= get_object_or_404(Client, pk=pk)
if request.method=='POST':
#populate the form with data from the request
# formset = PreorderHasProductsForm(request.POST)
if formset.is_valid():
is_successed=1
preorder_date=formset.cleaned_data['preorder_date']
product=formset.cleaned_data['preorder_has_products']
return render(request, template_name, {'preorder_date':preorder_date,'product':product,'is_successed':is_successed,'formset':formset})
return render(request, template_name, {'object':client,'formset':formset})
afterwards in your template you can just put the code below
{%if is_successed == 1 %}
<h1>{{preorder_date}}</h1>
<h2> {{product}}</h2>
{%endif %}
views.py
from django.contrib import messages
def view_name(request):
if request.method == 'POST':
form = form_class(request.POST)
if form.is_valid():
return HttpResponseRedirect('/thanks'/)
else:
messages.error(request, "Error")
return render(request, 'page.html', {'form':form_class()})
If you want to show the errors of the form other than that not valid just put {{form.as_p}} like what I did below
page.html
<html>
<head>
<script>
{% if messages %}
{% for message in messages %}
alert('{{message}}')
{% endfor %}
{% endif %}
</script>
</head>
<body>
{{form.as_p}}
</body>
</html>
@AamirAdnan's answer missing field.label; the other way to show the errors in few lines.
{% if form.errors %}
<!-- Error messaging -->
<div id="errors">
<div class="inner">
<p>There were some errors in the information you entered. Please correct the following:</p>
<ul>
{% for field in form %}
{% if field.errors %}<li>{{ field.label }}: {{ field.errors|striptags }}</li>{% endif %}
{% endfor %}
</ul>
</div>
</div>
<!-- /Error messaging -->
{% endif %}
UPDATE: Added a more detailed description of the formset errors.
Form.errors combines all field and non_field_errors. Therefore you can simplify the html to this:
template
{% load form_tags %}
{% if form.errors %}
<div class="alert alert-danger alert-dismissible col-12 mx-1" role="alert">
<div id="form_errors">
{% for key, value in form.errors.items %}
<span class="fieldWrapper">
{{ key }}:{{ value }}
</span>
{% endfor %}
</div>
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
{% endif %}
If you want to generalise it you can create a list_errors.html which you include in every form template. It handles form and formset errors:
{% if form.errors %}
<div class="alert alert-danger alert-dismissible col-12 mx-1" role="alert">
<div id="form_errors">
{% for key, value in form.errors.items %}
<span class="fieldWrapper">
{{ key }}:{{ value }}
</span>
{% endfor %}
</div>
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
{% elif formset.total_error_count %}
<div class="alert alert-danger alert-dismissible col-12 mx-1" role="alert">
<div id="form_errors">
{% if formset.non_form_errors %}
{{ formset.non_form_errors }}
{% endif %}
{% for form in formset.forms %}
{% if form.errors %}
Form number {{ forloop.counter }}:
<ul class="errorlist">
{% for key, error in form.errors.items %}
<li>{{form.fields|get_label:key}}
<ul class="errorlist">
<li>{{error}}</li>
</ul>
</li>
{% endfor %}
</ul>
{% endif %}
{% endfor %}
</div>
</div>
{% endif %}
form_tags.py
from django import template
register = template.Library()
def get_label(a_dict, key):
return getattr(a_dict.get(key), 'label', 'No label')
register.filter("get_label", get_label)
One caveat: In contrast to forms Formset.errors does not include non_field_errors.
simply you can do like this because when you initialized the form in contains form data and invalid data as well:
def some_func(request):
form = MyForm(request.POST)
if form.is_valid():
//other stuff
return render(request,template_name,{'form':form})
if will raise the error in the template if have any but the form data will still remain as :
This answer is correct but has a problem: fields not defined. If you have more then one field, you can not recognize which one has error.
with this change you can display field name:
{% if form.errors %}
{% for field in form %}
{% for error in field.errors %}
<div class="alert alert-danger">
<strong>{{ field.label }}</strong><span>{{ error|escape }}</strong>
</div>
{% endfor %}
{% endfor %}
{% for error in form.non_field_errors %}
<div class="alert alert-danger">
<strong>{{ error|escape }}</strong>
</div>
{% endfor %}
{% endif %}
def some_view(request):
if request.method == 'POST':
form = SomeForm(request.POST)
if form.is_valid():
return HttpResponseRedirect('/thanks'/)
else:
form = SomeForm()
return render(request, 'some_form.html', {'form': form})
Source: Stackoverflow.com