交互式下拉列表 django 带有添加新条目的选项

Question

I am relatively new to django. I have made a simple app which enable a user to record details regarding a run (Activity). The user enters data such as: distance, time, route name, date ran..etc using a django ModelForm.

I have a ModelForm which enables the logged on user to add an Activity to the model database.

How do I get the form to add a drop down list of all the routes which are already in the model database AND add a new one if the Person is entering data about a route they haven't ran before.?

class Person(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    fName = models.CharField(max_length =100)
    lName = models.CharField(max_length =100)
    weight = models.FloatField()
    sex = models.CharField(max_length=10)

    def __str__(self):
        return self.lName

class Activity(models.Model):
    person = models.ForeignKey(Person, on_delete=models.CASCADE)
    length = models.FloatField()
    runTime = models.DurationField()
    route = models.CharField(max_length=100)
    ave = models.DurationField()
    dateRun = models.DateField()
    marathon = models.DurationField()

    def __str__(self):
        return self.route ```

Answer 1

I would add model Route in models.py:

class Person(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    fName = models.CharField(max_length=100)
    lName = models.CharField(max_length=100)
    weight = models.FloatField()
    sex = models.CharField(max_length=10)

    def __str__(self):
        return self.lName


class Route(model.model):
    person = models.ForeignKey(Person, on_delete=models.CASCADE)
    length = models.FloatField()
    route = models.CharField(max_length=100)
    
    
class Activity(models.Model):
    person = models.ForeignKey(Person, on_delete=models.CASCADE)
    runTime = models.DurationField()
    route =  models.ForeignKey(Route, on_delete=models.CASCADE)
    ave = models.DurationField()
    dateRun = models.DateField()
    marathon = models.DurationField()

    def __str__(self):
        return self.route

When person wants to add activity he will have all routes that he enters before. That solution require additional job in modelform, and need of another form to add new route. I think the ActivityForm should look like:

class ActivityForm(forms.ModelForm):
    class Meta:
        model = Activity
        fields = '__all__'
        widgets = {'person': forms.HiddenInput}

and init it in views.py:

form = ActivityForm(initial={'person': request.user.id})
form.field['route'].queryset = Route.objects.filter(person=request.user)