remembering form field value on django model form

Question

I am quite new to Django as such, and have been playing around with ModelForms. So far, I have been able to create ModelForms with ease. However, one problem seems to bug me a bit:

When a user fills the form, and if there is an error (say int instead of char or a missing blank=False value), the form spits out the error and seems to forget the values the user entered when the form failed to validate. I am wondering if there is a way to remember these values so that the user does not have to enter them again.

At the moment, I have something like the following:

class ContactForm(CreateView):

    form_class = ContactForm
    template_name = "superform.html"
    success_url = '/ty/'

    def form_valid(self, form):
        # do something useful with validated form
        return super(ContactForm, self).form_valid(form)

    def form_invalid(self, form):
        # do something useful with invalidated form.
        return super(ContactForm,self).form_invalid(form)

I am assuming I need to do something in form_invalid to pass the values back to the form - but I am unsure how to do this(?).

I would really appreciate if someone could point me in the right direction.

Thanks.

----Edit---

            <form class="form" role="form" action="{% url 'coolurl' %}" method="post">{% csrf_token %}

                    {% if form.non_field_errors %}
                      <div class="alert">
                      {% for error in form.non_field_errors %}
                      <span class="label">Error: {{ error|escape }}</span> 
                      {% endfor %}
                      </div>
                    {% endif %}


                    <div class="form-group">
                        {% if form.name.errors %}
                          <div class="alert">
                          {% for error in form.name.errors %}
                          <span class="label">Error: {{ error|escape }}</span> 
                          {% endfor %}
                          </div>
                        {% endif %}

                        <label class="col-sm-3" for="id_name">Name:</label>
                        <div class="col-sm-6">
                        <input class="form-control" 
                             id="id_name" 
                             type="text" 
                             name="name" 
                             maxlength="128" 
                             placeholder="Your name..">
                        </div>
                    </div>

                    <button type="submit" class="btn btn-success">Submit</button>
            </form>

Answer 1

You've taken the responsibility for rendering those fields away from Django by simply hard-coding them in the HTML. That means that Django has no way of inserting the current values; not only when redisplaying after errors, but also if you have a form that modifies existing database content.

Don't do it like that. I understand that you don't want to just juse form.as_p, but there is a good middle ground: output each field in the template with {{ form.my_field }}. You can add relevant classes to the fields in the definition in forms.py, and then Django will take care of outputting it correctly.

Answer 2

Try to mention the value of the input tag:

<input class="form-control" 
                             id="id_name" 
                             type="text" 
                             name="name" 
                             maxlength="128"
                             value="{{ form.name.value|default_if_none:'' }}"
                             placeholder="Your name..">
                        </div>