Question

好吧，这是第三天寻找该错误的解决方案，所以我只想在这里问。

我知道还有其他与我类似的问题，但显然其他所有问题都有另一个原因。这是我的设置： Django版本：2.1.5 Python版本：3.7.1

我的错误是这样的：

ValueError at /testsel

too many values to unpack (expected 2)

这是我的回溯：

Traceback (most recent call last):
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/core/handlers/base.py", line 124, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/ricardo/Projects/Organizacional/organizacional/home/views.py", line 36, in testsel
    return render(request,'home/testsel.html',{ 'form':form })
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/shortcuts.py", line 36, in render
    content = loader.render_to_string(template_name, context, request, using=using)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/loader.py", line 62, in render_to_string
    return template.render(context, request)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 171, in render
    return self._render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 163, in _render
    return self.nodelist.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 937, in render
    bit = node.render_annotated(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
    return self.render(context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 993, in render
    return render_value_in_context(output, context)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/template/base.py", line 972, in render_value_in_context
    value = str(value)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/utils/html.py", line 397, in <lambda>
    klass.__str__ = lambda self: mark_safe(klass_str(self))
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 142, in __str__
    return self.as_table()
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 284, in as_table
    errors_on_separate_row=False,
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 202, in _html_output
    top_errors = self.non_field_errors()  # Errors that should be displayed above all fields.
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 313, in non_field_errors
    return self.errors.get(NON_FIELD_ERRORS, self.error_class(error_class='nonfield'))
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 180, in errors
    self.full_clean()
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 381, in full_clean
    self._clean_fields()
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/forms.py", line 393, in _clean_fields
    value = field.widget.value_from_datadict(self.data, self.files, self.add_prefix(name))
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/forms/widgets.py", line 648, in value_from_datadict
    return getter(name)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/query.py", line 390, in get
    clone = self.filter(*args, **kwargs)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/query.py", line 844, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/query.py", line 862, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1263, in add_q
    clause, _ = self._add_q(q_object, self.used_aliases)
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1287, in _add_q
    split_subq=split_subq,
  File "/home/ricardo/anaconda3/lib/python3.7/site-packages/django/db/models/sql/query.py", line 1161, in build_filter
    arg, value = filter_expr
ValueError: too many values to unpack (expected 2)

这是在views.py中调用的函数：

def testsel(request):
    if request.method=="POST":
        pass #just testing for now
    else:
        form=SelectTest(Tests.objects.all())
    return render(request,'home/testsel.html',{ 'form':form })

这是在forms.py中定义的表单：

class SelectTest(forms.Form):
    def __init__(self, *args, **kwargs):
        super(SelectTest,self).__init__(*args,**kwargs)
        CHOICES=args[0].values('sigla')
        CHOICES=[(s['sigla'],s['sigla'].lower()) for s in CHOICES]
        self.fields['select']=forms.ChoiceField(widget=forms.Select(),choices=CHOICES)

这是我的模板

{% block content %}
<form action="" method="post">{% csrf_token %}
    {{ form }} 
  <button type="submit">Enviar</button>
</form>
{% endblock content %}

这是在views.py中调用的测试（尽管我认为这并不重要）：

class Tests(models.Model):
    name = models.CharField(max_length=100)
    sigla = models.CharField(max_length=10)
    instruction = models.TextField()
    about = models.TextField()
    nquestions = models.PositiveIntegerField()
    table = models.CharField(max_length=10)

现在，如果我将模板更改为此：

{% for field in form %}
    {{ field.select }}
{% endfor %}

它呈现没有错误，但是表单没有呈现，或出现在“查看源代码”中。如果我在循环内仅使用field，则会返回到“要解压缩的值太多”。

我知道我需要在选择时传递一个元组列表，这就是完成的工作。我已经对其进行了三重检查。

感谢任何帮助。

Answer 1

表单的第一个参数是与其绑定的数据。您要在此处传递查询集，然后立即将其传递给超类，这会导致错误。

如果要向表单传递额外的数据，则应始终使用关键字参数，并在调用super之前将其从kwargs字典中删除。

form=SelectTest(sigla=Tests.objects.all())

...

class SelectTest(forms.Form):
    def __init__(self, *args, **kwargs):
        sigla = kwargs.pop('sigla', None)
        super(SelectTest,self).__init__(*args,**kwargs)

请注意，您可能应该使用ModelChoiceField-直接接受查询集-而不是简单的ChoiceField。

在模板中呈现表单时发生ValueError

1 个答案: