forms.ModelForm 不保存 ManyToMany 字段

Question

我正在使用表单 (forms.ModelForm)，当我基于模型创建表单时，我遇到了一些小不便。我的情况，例如在我的models.py 文件中：

我有CorporalSegment 型号：

class CorporalSegment(models.Model):
    SEGMENTO_HOMBRO = 'Hombro'
    SEGMENTO_CODO = 'Codo'
    SEGMENTO_ANTEBRAZO = 'Antebrazo'
    SEGMENTO_MANO = 'Mano'

    SEGMENT_CHOICES = (
        (SEGMENTO_HOMBRO, u'Hombro'),
        (SEGMENTO_CODO, u'Codo'),
        (SEGMENTO_ANTEBRAZO, u'Antebrazo'),
        (SEGMENTO_MANO, u'Mano'),
    )

    corporal_segment = models.CharField(
        max_length=12,
        choices=SEGMENT_CHOICES,
        blank=False,
    )

    class Meta:
        verbose_name_plural = 'Segmentos Corporales'

    def __str__(self):
        return "%s" % self.corporal_segment

我有Movement 模型

class Movements(models.Model):
    name = models.CharField(
        max_length=255,
        verbose_name='Movimiento'
    )
    class Meta:
        verbose_name_plural = 'Movimientos'

    def __str__(self):
        return "%s" % self.name

我有Metric 模型

class Metrics(models.Model):
    name = models.CharField(
        max_length=255,
        blank=True,
        verbose_name='Nombre'
    )
    value = models.DecimalField(
        max_digits = 5,
        decimal_places = 3,
        verbose_name = 'Valor',
        null = True,
        blank = True
    )

    class Meta:
        verbose_name = 'Métrica'

    def __str__(self):
        return "{},{}".format(self.name, self.value)

我的目的是，在一种形式中，我可以保存CorporalSegment、Movement 和Metric 模型的多个值（实例），因此，我有这种方式的PatientMonitoring 模型：

class PatientMonitoring(models.Model):

    patient = models.ForeignKey(...)
    medical = models.ForeignKey(...)

    # My fields pointing to my previous models with many to many relationship
    corporal_segment = models.ManyToManyField(CorporalSegment, verbose_name='Segmentos Corporales')
    movement = models.ManyToManyField(Movements, verbose_name='Movimientos')
    metrics = models.ManyToManyField(Metrics, verbose_name='Métricas', )

    class Meta:
        verbose_name = 'Monitoreo del paciente'

    def __str__(self):
        return "%s" % self.patient

我的views.py 文件

class PatientMonitoringCreate(CreateView):
    model = PatientMonitoring
    form_class = PatientMonitoringForm
    success_url = reverse_lazy('patientmonitoring:list')

class PatientMonitoringUpdate(UpdateView):
    model = PatientMonitoring
    form_class = PatientMonitoringForm
    success_url = reverse_lazy('patientmonitoring:list')

我的forms.py是这样的：

from django import forms

from .models import PatientMonitoring

from crispy_forms.helper import FormHelper
from crispy_forms.layout import Submit

class PatientMonitoringForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(PatientMonitoringForm, self).__init__(*args, **kwargs)
        self.helper = FormHelper()
        self.helper.add_input(Submit('submit', u'Save'))

    # I think so that here is my problem ...
    def save(self, commit=True):
        patient_monitoring = super(PatientMonitoringForm, self).save(commit=False)
        patient = self.cleaned_data['patient']

        if commit:
            patient_monitoring.save()
        return patient_monitoring

    class Meta:
        model = PatientMonitoring
        fields = ['patient', 'medical','corporal_segment','movement','metrics']

而我的模板patientmonitoring_form.html 是：

{% extends 'base.html' %}
{% load crispy_forms_tags %}
{% block title %}Crear Registro de Monitoreo de Paciente{% endblock %}
{% block content %}

<div>
    {% crispy form %}
    {% csrf_token %}

</div>
{% endblock %}

当我想以各自的形式保存 PatientMonitoring 实例时，corporal_segment (Segmentos Corporales) movement (Movimientos) 和 metrics (Metricas) 字段在表单中，它们的值不会保存在表单（红色方块），但其他字段被保存（不是红色方块）

这种行为对我来说很奇怪，因为通过 Django 管理表单，可以保存一个 PatientMonitoring 实例及其所有属性。

在我的PatientMonitoringFormPatientMonitoringForm 文件中的save 方法中保存时，我会忽略什么？

Answer 1

https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#the-save-method

使用commit=False时，必须调用save_m2m()

m2m 关系需要先保存父对象，而您没有使用 commit=False。