I just had a formset where each form had a pre-loaded ModelChoiceField, and I needed to display the name of the selected choice in the template.  On a model you would just use the get_FOO_display() method, but a form has no such convenience.  I found a number of almost solutions on Stack Overflow, and after poring over them I concluded the best solution for my problem was to add the following method to the form:

class QuestionLanguageForm(forms.Form):
    ''' basic QuestionLanguage form '''
    language = forms.ModelChoiceField(queryset=Language.objects.all())
    short = forms.CharField()
    place_holder = forms.CharField()
    long = forms.CharField(widget=forms.Textarea(attrs={'rows':None, 'cols':None}))

def get_language_name(self):
    ''' returns the name of the selected language '''
    try:
       return Language.objects.get(id=self.initial['language']).name
    except:
       return None

This way I can use

{{ form.get_language_name }}

in my template and it prints the human readable name of the language set in my initial data.  This code is not robust; I catch all exceptions and ignore them because I’m only using it in a circumstance where this code won’t raise an exception (and in case it does, at least it won’t fail catastrophically).  However proper error handling could be added pretty simply.  #ExerciseForTheReader

P.S.  The title says “selected” value but I’m actually using a pre-loaded value, not anything user selected.  If you need to get a user selected value you could use self.data or self.cleaned_data instead of self.initial.

I just searched for a method to convert a model instance to a dictionary in Django and the top few results were a bunch of custom methods in Django Snippets and Stack Overflow.  I was about to use one of those when I clicked on one last link that showed me a better solution.  There is a method already built into Django that does exactly what I want: django.forms.models.model_to_dict.

As I pointed that out to a coworker, he showed me that that’s basically the same output as the .values() method in the queryset api.  If you don’t specify a value to retrieve, it will retrieve the whole model instance as a dictionary.

Here’s the output of these two pieces of code:

>>> Q.objects.filter(id=6).values()
[{'short': u'oui', 'deleted': False, 'language_id': 3L, 'long': u'oui', 'place_holder': u'oui', 'id': 6L, 'question_id': 8L}]
>>> model_to_dict(Q.objects.filter(id=6)[0])
{'short': u'oui', 'language': 3L, 'deleted': False, 'question': 8L, 'long': u'oui', 'place_holder': u'oui'}

There are two differences here, and one of them is pretty important.  First, .values() turns a queryset into an iterable that yields dictionaries, and model_to_dict turns a model instance into a single dictionary.  As long as you know about it this is pretty trivial to overcome.  Second, .values() converts foreign keys to {‘<field_name>_id’: #} and model_to_dict converts them to {‘<field_name>’: #}.  Since my purpose in using this was to populate a form I had to convert the id’s into model instances and update the dictionary.  Not a big problem, but a bigger annoyance to solve than the first difference.