title: Using dynamic Choice Field in Django
body: <p>I have a <code>choiceField</code> in order to create a select field with some options. Something like this:</p>
  
  <pre><code>forms.py
      class NewForm(forms.Form):
          title = forms.CharField(max_length=69)
          parent = forms.ChoiceField(choices = CHOICE)
  </code></pre>
  
  <p>But I want to be able to create the options without having a predefined tuple (which is required by <code>ChoiceField</code>). Basically, I need to have access to request.user to fill some options tags according to each user, but I don't know if there is any way to use request in classes of forms.Form.</p>
  
  <p>An alternative would be to prepopulate the instance of <code>NewForm</code> via:</p>
  
  <pre><code>views.py
  form = NewForm(initial={'choices': my_actual_choices})
  </code></pre>
  
  <p>but I have to add a dummy CHOICE to create NewForm and my_actual_choices doesn't seem to work anyway.</p>
  
  <p>I think a third way to solve this is to create a subclass of ChoiceField and redefined <code>save()</code> but I'm not sure how to go about doing this.</p>