Python 3.x 如何在django中创建拾取电子邮件字段

我正在创建一个邮件系统管理应用程序。因此，根据附件图，当系统中已经存在我要向其发送电子邮件的客户电子邮件地址时，我希望在A字段中显示他们来自此字段的电子邮件。否则，我们将键入完整的电子邮件地址，然后提交表单。 这是

models.py

class Contacts(models.Model):
    type_Contact_choice=(
        ('Agent','Agent'),
        ('Association','Association'),
        ('Autre','Autre'),
        ('Collectivité','Collectivité'),
        ('Conseil minicipal','Conseil minicipal'),
        ('Elu','Elu'),
        ('Particulier','Particulier'),
        ('Précture','Précture'),
        ('Société','Société'),
        )
    civilite_choice=(
        ('Monsieur','Monsieur'),
        ('Madame','Madame'),
        ('M. et Mme','M. et Mme'),
        ('Monsieurs','Monsieurs'),
        ('Mesdames','Mesdames'),
        )
    category_choice=(
        ('Personnel','Personnel'),
        ('Externe','Externe'),
        )
    nom = models.CharField(max_length=200, null=False)
    type_contact = models.CharField(_('Type'), choices=type_Contact_choice, max_length=200, null=True, )
    category = models.CharField(_('Catégorie du contact'), choices=category_choice, max_length=50, null=True, blank=True)
    prenom = models.CharField(_('Prénom'), max_length=200, null=False)
    civilite = models.CharField(_('Civilité'), choices=civilite_choice,max_length=200,null=True, blank=True)
    fonction = models.CharField(max_length=200, null=True, blank=True)
    telephone = models.CharField(blank=True, null=True, max_length=16)
    adresse = models.TextField()
    mobile = models.CharField(blank=True, null=True, max_length=16)
    email = models.EmailField(blank=True, null=True)
    divers = models.TextField(blank=True, null=True)
    service = models.CharField(max_length=300, blank=False, null=False)

    def __str__(self):

        return self.nom + ' '+self.prenom


class Actions(models.Model):
    statut_action_choice=(
        ('Encours','Encours'),
        ('En attente','En attente'),
        ('Terminée','Terminée'),
        ('Annulé','Annulé')
        )
    action_date =models.DateTimeField(auto_now_add=True)
    action_modification = models.DateTimeField(auto_now=True)
    de = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
    a = models.ForeignKey(Contacts, on_delete=models.CASCADE, null=False)
    cc = models.EmailField(max_length=254,null=True,blank=True)
    file = models.FileField(_('Document joint'),upload_to='action/%Y/%m/%d', blank=True)
    statut = models.CharField(max_length=30, choices=statut_action_choice, default='Encours')
    action = RichTextField(_('Actions'))
    history = HistoricalRecords()

views.py

@login_required(login_url='/account/login')
def add_action(request):
    if request.method == 'POST':
        form = ActionForm(request.POST, request.FILES)
        if form.is_valid():
            email_to=form.cleaned_data['a']
            cc = form.cleaned_data['cc']
            action=form.save(commit=False)
            action.de = request.user
            action.save()
            email_subject = 'Vous avez une action à exeducter'
            email_from = 'example@mails.com'
            email_body = 'Cher vous avez reçu une notification pour action. Veuillez ne pas ' \
                         'répondre à cette notification.'

            email=EmailMessage(email_subject,
                      email_body,
                      email_from,
                      [email_to,],
                      [cc],
                      )
            email.send(fail_silently=False)
            return redirect(reverse('courriers:list_courrier'))
    else:
        form = ActionForm()
    return render(request,
                  'courriers/actions/add_action.html',
                  {'form':form})

我的模板

{% extends 'base.html' %}
{% block content %}
{% load crispy_forms_tags %}
<div class="form-group">
    <form action="." method="post" enctype="multipart/form-data">
        {% csrf_token %}
        {{form.media}}
        {{form|crispy}}
    <button type="submit" class="btn btn-primary"> Enregistrer </button>
    </form>
</div>
{% endblock %}

{%extends'base.html%}
{%block content%}
{%load crispy_forms_tags%}
{%csrf_令牌%}
{{form.media}
{{form | crispy}}
登记员
{%endblock%}