默认情况下是否有可能在 Django 中的 ManyToManyField 生成的多选中选择所有选项？
添加的所有新项目都应在视图中预先选择所有选项（添加AnotherEntity 的新项目时也是如此）。
class AnotherEntity(models.Model):
name = models.CharField()
class SomeEntity(models.Model):
anotherEntity = models.ManyToManyField(AnotherEntity)
在上面的示例中，我希望在所有新项目中选择anotherEntity 中的所有选项。
【问题讨论】：
标签： django django-models django-forms django-suit
只需继承SelectMultiple 小部件并覆盖： 1)render_option 以呈现所有选定的内容； 2) render_options 控制我们在哪里渲染所有选定的以及默认的渲染位置。
class CustomSelectMultiple(SelectMultiple):
def render_options(self, choices, selected_choices):
if not selected_choices:
# there is CreatView and we have no selected choices - render all selected
render_option = self.render_option
else:
# there is UpdateView and we have selected choices - render as default
render_option = super(CustomSelectMultiple, self).render_option
selected_choices = set(force_text(v) for v in selected_choices)
output = []
for option_value, option_label in chain(self.choices, choices):
if isinstance(option_label, (list, tuple)):
output.append(format_html('<optgroup label="{0}">', force_text(option_value)))
for option in option_label:
output.append(render_option(selected_choices, *option))
output.append('</optgroup>')
else:
output.append(render_option(selected_choices, option_value, option_label))
return '\n'.join(output)
def render_option(self, selected_choices, option_value, option_label):
option_value = force_text(option_value)
selected_html = mark_safe(' selected="selected"')
return format_html('<option value="{0}"{1}>{2}</option>',
option_value,
selected_html,
force_text(option_label))
然后在表单中将小部件设置为您的字段：
class SomeEntityModelForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(SomeEntityModelForm, self).__init__(*args, **kwargs)
self.base_fields['anotherEntity'].widget = CustomSelectMultiple()
class Meta:
model = SomeEntity
【讨论】：
if option_value in selected_choices: github.com/django/django/blob/master/django/forms/… 所以也许你应该通过 js 来执行此操作或在 updateview 中切换到默认小部件 SelectMultiple
some_field 应该是什么？
你可以override这样保存模型的方法：
class SomeEntity(models.Model):
anotherEntity = models.ManyToManyField(AnotherEntity)
def save(self, *args, **kwargs):
choices = AnotherEntity.objects.all()
for choice in choices:
self.anotherentity.add(choice)
super(SomeEntity, self).save(*args, **kwargs)
【讨论】：