问题
When I post my formset, I get a MultiValueDictKeyError. Specifically:
MultiValueDictKeyError at /core/customers/1/update/documents/
"Key u'documents-0-attachment_ptr' not found in <QueryDict: {u'documents-1-last_modified_date': [u''], u'documents-1-name': [u''], u'documents-MAX_NUM_FORMS': [u''], u'documents-0-attachment_file': [u''], u'documents-INITIAL_FORMS': [u'1'], u'documents-1-document_type': [u''], u'documents-0-notes': [u''], u'documents-1-notes': [u''], u'submit': [u'Submit changes'], u'documents-0-DELETE': [u'on'], u'documents-1-attachment_file': [u''], u'documents-0-document_type': [u''], u'documents-TOTAL_FORMS': [u'2'], u'documents-0-name': [u'test'], u'documents-1-creation_date': [u''], u'documents-0-creation_date': [u'2012-12-01 23:41:48'], u'csrfmiddlewaretoken': [u'NCQ15jA7erX5dAbx20Scr3gWxgaTn3Iq', u'NCQ15jA7erX5dAbx20Scr3gWxgaTn3Iq', u'NCQ15jA7erX5dAbx20Scr3gWxgaTn3Iq'], u'documents-0-last_modified_date': [u'2012-12-01 23:41:48']}>"
The key part is that Django is looking for the key documents-0-attachment_ptr in the post data. This is confusing -- a Document is a subclass of an Attachment. All of the other post data is as expected. Why is Django needing pointer data in my formset?
Here is the form used in the formset:
class DocumentInlineForm(forms.ModelForm): # pylint: disable=R0924
attachment_file = forms.FileField(widget=NoDirectoryClearableFileInput)
notes = forms.CharField(
required=False,
widget=forms.Textarea(attrs={'rows': 2,}),
)
helper = DocumentInlineFormHelper()
class Meta: # pylint: disable=W0232,R0903
fields = (
'attachment_file',
'creation_date',
'document_type',
'last_modified_date',
'name',
'notes',
)
model = Document
And here is the Document model:
"""
Handles document model definitions.
"""
from django.db import models
from eee_core.models.attachments import Attachment
from django.db.models.signals import pre_save
from datetime import datetime
from django.utils.timezone import utc
class Document(Attachment):
"""
A document is an attachment with additional meta data.
"""
creation_date = models.DateTimeField(
blank=True,
null=True,
)
document_type = models.CharField(
blank=True,
choices=(
('CONTRACT', 'Contract'),
('INVOICE', 'Invoice'),
('FACILITY', 'Facility change form'),
('LOA', 'Letter of authorization'),
('USAGE', 'Usage history document'),
('OTHER', 'Other'),
),
default=None,
null=True,
max_length=8,
)
last_modified_date = models.DateTimeField(
blank=True,
null=True,
)
notes = models.TextField(
blank=True,
null=True,
)
class Meta(Attachment.Meta): # pylint: disable=W0232,R0903
"""
Sets meta fields for model.
"""
app_label = 'core'
def __str__(self):
return unicode(self).encode('utf-8')
def __unicode__(self):
return unicode(self.name)
def pre_save_callback(sender, instance, *args, **kwargs): # pylint: disable=W0613
if not isinstance(instance, Document):
return
if not instance.creation_date:
instance.creation_date = datetime.utcnow().replace(tzinfo=utc)
instance.last_modified_date = datetime.utcnow().replace(tzinfo=utc)
pre_save.connect(pre_save_callback, dispatch_uid='document_pre_save')
Additional info:
Curiously, the inital post of the formset works fine. It is only on update posts -- when there are initial forms in the formset -- when I get this error. It also happens when I try to delete forms from the formset.
Also, the formset is a generic inline formset using django crispy forms.
Update
There was a request for the template code used. Here is the simplified version:
{% load crispy_forms_tags %}
{% load url from future %}
<form action="" method="post" enctype="multipart/form-data">
{{ formset.management_form }}
{% for subform in formset.forms %}
{{ subform.id }}
{% crispy subform %}
{% endfor %}
<div class="btn-toolbar">
<input class='btn btn-primary' type="submit" name="submit" value="Submit changes" />
</div>
</form>
回答1:
This isn't the case with OP, but you will encounter a MultiValueDictKeyError, if some of the hidden fields are missing in the template. It may happen when instead of quick and dirty {{form}}, fields are listed in the template one by one: {{form.field1}}, {{form.field2}}, while leaving out required hidden fields.
To include them back do something along the lines (for each form/form in formset):
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
or
{% for form in formset %}
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
{% endfor %}
回答2:
I use also
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
like this one
<div role="tabpanel" class="tab-pane active" id="email">
{% csrf_token %}
{{ eformset.management_form}}
<div class="panel panel-default">
<div class="panel-body">
<div id="addemail" class="btn btn-success">
<span class="glyphicon glyphicon-plus" >
</span>
</div>
<p><br></p>
{% for f in eformset %}
{% for hidden in f.hidden_fields %}
{{ hidden }}
{% endfor %}
<div class="item_email_set">
<table class="table table-condensed table-bordered">
<tr>
{% for field in f.visible_fields %} <!---->
<td>
{{ field.label }}
</td>
{% endfor %}
<td>
</td>
</tr>
<tr>
{% for field in f.visible_fields %}
<td>
{{field.errors.as_ul}}
{{field}}
</td>
{% endfor %}
<td class="btncolumn">
<p style="">
<a class="delete_email_set" href="#">
<div class="btn btn-danger">
<span class="glyphicon glyphicon-remove" >
</span>
</div>
</a>
</p>
</td>
</tr>
</table>
</div>
{% endfor %}
</div>
</div>
</div>
and I resolve the MultiValueDictKeyError
回答3:
I stopped this error by adding attachment_ptr to the field list of my form. So DocumentInlineForm is now:
class DocumentInlineForm(forms.ModelForm): # pylint: disable=R0924
attachment_file = forms.FileField(widget=NoDirectoryClearableFileInput)
notes = forms.CharField(
required=False,
widget=forms.Textarea(attrs={'rows': 2,}),
)
helper = DocumentInlineFormHelper()
class Meta: # pylint: disable=W0232,R0903
fields = (
'attachment_ptr',
'attachment_file',
'creation_date',
'document_type',
'last_modified_date',
'name',
'notes',
)
model = Document
Maybe it is something I didn't know before, but does Django require you to provide a pointer to the superclass in all forms that use a subclassed model? This surprises me.
I'd like to find out why this pointer field is required, so I've opened a question to address that here: Why does my django formset need a pointer field reference?.
回答4:
This is not the answer to the OP but I got the same error. I mistakenly removed {{ subform.id }} from my template as I couldn't visually see it and I was tidying up old code.
In your HTML you will get something like:
<input name="note_set-0-id" value="34632" id="id_note_set-0-id" type="hidden">
来源：https://stackoverflow.com/questions/13666852/how-to-debug-a-django-multivaluedictkeyerror-on-formset-post