如何遍历下拉模型表单字段以仅显示Django中的某些值

Question

I have 4 choices

target = (('Week', 'Weekly target'),
          ('Day', 'Daily target'),
          ('Verify', 'Verify'),
          ('Done', 'Done'))

and this is my model to implement the choices:

class GoalStatus(models.Model):

    target = models.CharField(max_length=100, choices=target, default="Week")
    name = models.ForeignKey(ScrummyUser, on_delete=models.CASCADE)
    goal_status = models.ForeignKey(ScrummyGoals, on_delete=models.CASCADE)

This is my Model form

class ChangeTaskForm(forms.ModelForm):

    class Meta:
        model = GoalStatus
        fields = '__all__'

and this is my html file

{% if user.is_authenticated %}
{% if request.user|has_group:"ADMIN" %}

    <form action="{% url 'myapp:move_goal' %}"  method="post">
        {% csrf_token %}
        {% for field in form.data.target %}
            {% for foo in field %}
                {% if foo == Day %}
                    {{ foo }}
                {% endif %}
            {% endfor %}

        {% endfor %}
    </form>

How do I iterate through the drop down list in my form to display only a desired choice say 'Day' for a user that has permission to choose only 'Day'. I am very new to Django.

Answer 1

All the logic can be done in backend ( your views ) before sending the form to template:

if request.user.groups.filter(name__iexact="ADMIN").exists():
    form.fields['target'].choices = ( ('Day', 'Daily target'))

Since you're using Django CBV, override get_form() method

def get_form(self, *args, **kwargs):
    form = super(ClassBasedView, self).get_form(*args, **kwargs)
    if self.request.user.groups.filter(name__iexact="ADMIN").exists():
        form.fields['target'].choices = ( ('Day', 'Daily target'))
    return form

Answer 2

You can modify the choices in the ModelForm ( ModelForm documentation here ).

In your form:

from ____ import target # idk where your target variable is but it needs to be visible to your ChangeTaskForm in here. So you may have to import it.

class ChangeTaskForm(forms.ModelForm):

    class Meta:
        model = GoalStatus
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super(ChangeTaskForm, self).__init__(*args, **kwargs)
        self.initialize_widgets()

    def initialize_widgets(self):
        """
        Initializes widgets for the form. This is not a built in
        method. It's a method I'm adding. You can manipulate any field 
        in the form along with their widgets. This is where the choices 
        can be filtered down from the overall choices to specific 
        choices.
        """
        target_choices_for_field = []
        for target_option_tuple in target: # loop through each option.
            can_choose_option = ... # This is where you do the logic to determine whether or not the option should be available.
            if can_choose_option:
                target_choices_for_field.append(target_option_tuple)
        self.fields["target"].widget = forms.Select(choices=target_choices_for_field)

Then, in your html:

{% if user.is_authenticated %}
{% if request.user|has_group:"ADMIN" %}

<form action="{% url 'myapp:move_goal' %}"  method="post">
    {% csrf_token %}
    {% form %}
    <input type="submit" value="submit">Submit</input>
</form>

Now, the ModelForm has already dealt with filtering the options in the code so you don't need to do anything about that in the template. It's generally a good idea to push logic like that down the stack as much as possible. So form choices should be set in the form class, not the template. As a side note, the same thing (pushing logic as far down as possible) should be done with your validation. Use view decorators along with @user_passes_test to deal with groups to do authentication.