以一种形式创建一个对象及其与外场的多对多关系

Question

我使用的是 Django 2.2，这是我的简化模型：

class Course(CustomModelClass):
    name = models.CharField(max_length=200, null=False, unique=True)
    components = models.ManyToManyField('Component', through='CourseComponent')

class Component(CustomModelClass):
    name = models.CharField(max_length=200, null=False, unique=True)

class CourseComponent(CustomModelClass):
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    component = models.ForeignKey(Component, on_delete=models.CASCADE)
    quantity = models.IntegerField(default=0, null=False)

我的人际关系很好，这没有问题。现在到了我做一个 ModelForm 来管理它的那一刻。

这是我现在的表格：

class CourseForm(ModelForm):
    class Meta:
        fields = ['name', 'group', 'components']
        model = Course

同样，如果我的数量有一个 null=True 参数，它工作得很好，但当然当我把它设置为 False 时，它​​显然不再工作了。

我想做的是在我的表单中提供一种选择组件并为每个组件设置数量的方法。我真的不在乎它看起来像一个带有组件名称和数字字段的复选框，或者是用于选择组件和数字字段的许多选择列表，这不是重要的部分。

更清楚地说，我想创建一个对象及其与额外字段的多对多关系以相同的形式。

我现在的问题是我当然无法访问表格中的数量。

有什么想法吗？

Answer 1

我希望你觉得这个提议很有趣：

Views.py：

def view1(request):
    CourseComponentFormSet = formset_factory(CourseComponentForm, extra=Component.objects.count())
    content = {'form': CourseComponentFormSet}
    return render(request, 'stack/edit.html', content)


def view2(request, mycourse):
    if request.method == 'POST':
        data = {}
        for p in request.POST:
            if p.startswith('form'):
                data[p] = request.POST[p]
        j = 0
        while j < int(data['form-MAX_NUM_FORMS']):
            if data['form-' + str(j) + '-quantity'] == '':
                data['form-' + str(j) + '-quantity'] = 0
                data['form-' + str(j) + '-course'] = mycourse
            else:
                data['form-' + str(j) + '-course'] = mycourse
            j += 1
        CourseComponentFormSet = formset_factory(CourseComponentForm)
        formset = CourseComponentFormSet(data)
        if formset.is_valid():
            j = 0
            mylist = []
            while j < int(data['form-MAX_NUM_FORMS']):
                if data['form-' + str(j) + '-quantity'] == 0:
                    pass
                else:
                    Courses = get_object_or_404(Course, name=mycourse)
                    Components = get_object_or_404(Component, id=int(data['form-' + str(j) + '-component']))
                    Courses.components.add(Components,
                                           through_defaults={'quantity': data['form-' + str(j) + '-quantity']})
                j += 1

            return HttpResponseRedirect(reverse('stack:view1'))
        else:
            errors = formset.errors
            ini = []
            i = 0
            nb = Component.objects.count()
            while i < nb:
                ini.append({'course': mycourse})
                i += 1
            CourseComponentFormSet = formset_factory(CourseComponentForm, max_num=nb)
            formset = CourseComponentFormSet(initial=ini)
            content = {'form': formset, 'course': mycourse, 'errors': errors}
            return render(request, 'stack/edit.html', content)
    else:
        if Course.objects.filter(name__exact=mycourse):
            pass
        else:
            Course.objects.create(**{'name': mycourse})
        ini = []
        i = 0
        nb = Component.objects.count()
        while i < nb:
            ini.append({'course': mycourse})
            i += 1
        CourseComponentFormSet = formset_factory(CourseComponentForm, max_num=nb)
        formset = CourseComponentFormSet(initial=ini)
        content = {'form': formset, 'course': mycourse}
        return render(request, 'stack/edit.html', content)

模型.py

class Component(models.Model):
    name = models.CharField(max_length=200, null=False, unique=True)

    def __str__(self):
        return self.name


class Course(models.Model):
    name = models.CharField(max_length=200, null=False, unique=True)
    components = models.ManyToManyField('Component', through='CourseComponent')

    def __str__(self):
        return self.name


class CourseComponent(models.Model):
    component = models.ForeignKey(Component, on_delete=models.CASCADE)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    quantity = models.IntegerField(default=0, null=False)

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

forms.py

class CourseComponentForm(Form):

    course = CharField(label='Course')
    component = ChoiceField(label='Component')
    quantity = IntegerField(label='Quantity')

    def __init__(self, *args, **kwargs, ):
        super(CourseComponentForm, self).__init__(*args, **kwargs)
        self.fields['component'].choices = tuple(Component.objects.all().values_list(flat=False))
        self.fields['quantity'].widget.attrs['style'] = "margin:15px 56% 15px 0%;"
        self.fields['course'].widget.attrs['readonly'] = "True"
        self.fields['course'].widget.attrs['disabled'] = "disabled"

edit.html

<body>
<label>Course:</label><input id="myinput" type="text"><button onclick="myfunction()">send</button><br>'
    <form action='' id='myform' method="POST">
    {% csrf_token %}
    {{ form }}
        <button class="btn btn-primary" name="submit" onclick="submit()">submit</button>
     </form>
{{errors}}
</body>

<script>

{% if mycourse %}
{% endif %}

function submit() {
document.getElementById('myform').action="/stack/view2/"+mycourse;
document.getElementById("myform").submit();
}


function myfunction() {
    var course = document.getElementById("myinput").value;
    chemin ="\/stack\/view2\/"+course;
     window.location.replace(chemin);
}
</script>
</html>

Answer 2

直接在modelform中添加额外的字段：

from django import forms
from .models import Course, Component
class CourseForm(ModelForm):
    class Meta:
        fields = ['name']
        model = Course

class ComponentForm(forms.Form):
    component = forms.ModelChoiceField(queryset=Component.objects.all())
    quantity = forms.IntegerField(initial=0, required=False, min_value=0)

ComponentFormSet = forms.formset_factory(ComponentForm, extra=3)

views.py 相关

def handler(request):
    if request.method == "POST":
        form = CourseForm(request.POST)
        formset = ComponentFormSet(request.POST)
        if form.is_valid() and formset.is_valid():
            # do your business
    form = CourseForm()  #it could set initial data here for form,etc
    formset = ComponentFormSet()
    return render(request, 'your_template.html', {'form':form, 'formset':formset})

有关you_template.html

{% extends 'admin/base_site.html'%}
{% load i18n %}
{% block content%}
<div class="col-md-10">
    <form action={% url "course" %} method='post' role='form' class="form-inline">
        {% csrf_token %}
        {{ form }}<br>
        {{ formset.management_form}}
        {% for fm in formset %}
        {{ fm }}<br>
        {% endfor%}
        <input type='submit' class='btn btn-primary' value="submit"/>
    </form>
</div>
{% endblock%}