django display ManyToManyField as a form field - django

Question

I am trying to display a ManyToManyField in my template:
class GvtCompo(models.Model):
startDate=models.DateField(max_length=10, blank=False, null=False)
endDate=models.DateField(max_length=10, blank=False, null=False)
gvtCompo= models.CharField(max_length=1000, blank=False, null=False)
class Act(models.Model):
gvtCompo= models.ManyToManyField(GvtCompo)
In my view, I can display the object, no problem:
for gvtCompo in act.gvtCompo.all():
print gvtCompo.gvtCompo
In my template, I have a list of "GvtCompo Object" with this code (not nice):
{% for field in form %}
<div class="fieldWrapper">
{{ field.errors }}
{{ field }}
</div>
{% endfor %}
I have tried to make it nicer, but the following code just not work (nothing appears):
{% for field in form %}
{% if field.name == "gvtCompo" %}
{% for gvtCompo in field.gvtCompo.all %}
{{ gvtCompo.gvtCompo }}
{% endfor %}
{% endif %}
{% endfor %}
What's wrong?
*Edit: *
If I don't use the form but an instance of the model (act) passed to render_to_response it displays the ManyToManyField values
{% for gvtCompo in field.gvtCompo.all %}
changed to
{% for gvtCompo in act.gvtCompo.all %}
However there is not form field anymore, so it can't be modified, validated and saved!

Answer 1

You are skipping a step. You first need to create a form.
In forms.py you can create a ModelForm. A ModelForm is a form based on your model:
from django.forms import ModelForm
from myapp.models import Act
class ActForm(ModelForm):
class Meta:
model = Act
Then your view:
from myapp.models import Act
from myapp.forms import ActForm
def add_view(request):
if request.method == 'POST':
form = ArticleForm(request.POST)
if form.is_valid():
form.save()
else:
form = ActForm() # Creating a empty form.
return render_to_response("template.html", {
"form": form,
})
def edit_view(request):
obj = Act.objects.get(pk=1)
if request.method == 'POST':
form = ArticleForm(request.POST)
if form.is_valid():
form.save()
else:
form = ActForm(instance=obj) # Creating form pre-filled with obj.
return render_to_response("template.html", {
"form": form,
})
If you want to implement this situation more than once. DRY: https://docs.djangoproject.com/en/1.5/topics/class-based-views/intro/#handling-forms-with-class-based-views
In your template.html:
{{ form }}
Disclaimer: This code is not tested.
https://docs.djangoproject.com/en/1.5/ref/forms/
https://docs.djangoproject.com/en/1.5/topics/forms/modelforms/
Update:
You can pass multiple forms to one <form>...</form> in your template. So create two forms. One Act form (see above) and one GvtCompo formset. The formset contains all GvtCompo's that have a relation to Act.
from django.forms.models import modelformset_factory
act = Act.objects.get(pk=1) #The same act as you used to create the form above.
GvtFormSet = modelformset_factory(GvtCompo)
formset = GvtFormSet(queryset=act.gvtCompo.all())
Template can be:
<form ...>
{% for field in form %}
{% if field.name == "gvtCompo" %}
{{ formset }}
{% else %}
{{ field }}
{% endif %}
{% endfor %}
</form>
Note: If your form and formset have colliding field names use prefix="some_prefix":
Django - Working with multiple forms

Answer 2

When looping over the form, it should be:
{% for field in form %}
{% if field.name == "gvtCompo" %}
{% for gvtCompo in form.instance.gvtCompo.all %}
{{ gvtCompo.gvtCompo }}
{% endfor %}
{% endif %}
{% endfor %}
field itself has no related field.gvtCompo.