在Django中重新显示带有先前提交的错误数据的表单

Question

遇到错误后，如何使提交的数据重新显示在表单集中？ Django的书谈到了这一点，我能够使它以某种形式而不是某种形式工作。

方案：有2个必填字段-名和姓。 如果我仅在名字字段中输入'John'，而姓氏字段为空，然后单击Submit，我将收到一条错误消息，指出这两个字段都是必填字段，并且表单使用错误消息清除了提交的数据。 我想在名字字段中看到名字“ John”以及错误消息。

非常感激！

**forms.py**

from django import forms
from django.forms.formsets import BaseFormSet


class NameForm (forms.Form):

    first_name = forms.CharField (max_length = 20, required = False)
    last_name = forms.CharField (max_length = 20, required = False)


class BaseNameFormSet (BaseFormSet):

    def clean (self):
        if any (self.errors):
            return

        firstnames = []
        lastnames = []
        for form in self.forms:
            firstname = form.cleaned_data.get ('first_name')
            lastname = form.cleaned_data.get ('last_name')

            if (firstname in firstnames) or (lastname in lastnames):
                raise forms.ValidationError ('First or last name must be unique')
            if (firstname == '') or (lastname == ''):
                raise forms.ValidationError ('Both first and last name must be filled out')

            firstnames.append (firstname)
            lastnames.append (lastname)

        return self.cleaned_data


**views.py**

from django.shortcuts import render
from django.forms.formsets import formset_factory
from nameform.forms import NameForm
from nameform.forms import BaseNameFormSet
from nameform.addName import webform


# Create your views here.
def addname (request):

    # Set maximum to avoid default of 1000 forms.
    NameFormSet = formset_factory (NameForm, formset = BaseNameFormSet, extra = 2, max_num = 5)

    if request.method == 'POST':
        # Django will become valid even if an empty form is submitted. Adding initial data causes unbound form and
        # trigger formset.errors
        # formset = NameFormSet (request.POST, initial = [{'first_name': 'John', 'last_name': 'Doe'}])
        formset = NameFormSet (request.POST)

        if formset.is_valid ():
            location = request.POST ['site']
            data = formset.cleaned_data

            for form in data:
                # Retrieving the value in an empty dictionary will result key error as it doesn't exist
                # firstname = form ['first_name']
                # lastname = form ['last_name']

                firstname = form.get ('first_name')
                lastname = form.get ('last_name')

                if firstname and lastname:
                    webform (firstname, lastname, location)

            context = {'data': data, 'location': location}

            return render (request, 'nameform/success.html', context)

    else:
        formset = NameFormSet ()

    return render (request, 'nameform/addname.html', {
        'formset': formset,
        'first_name': request.POST.get ('first_name', ''),
        'last_name': request.POST.get ('last_name', '')
    })


**addname.html**

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>Add Name</title>
</head>
<body>
    <h1>Add Name</h1>
    <form action="" method="POST">{% csrf_token %}
        <h3>Location:</h3>
        <p><input type="radio" id="radio1" name="site" value="Location_A" checked>
        <label for="radio1">Location A</label>
        <input type="radio" id="radio2" name="site" value="Location_B">
        <label for="radio2">Location B</label></p>
        {{ formset.management_form }}
        <label for="id_form-0-first_name">First Name:</label>
        <input id="id_form-0-first_name" maxlength="20" name="form-0-first_name" type="text" value="{{ first_name }}" />
        <label for="id_form-0-last_name">Last Name:</label>
        <input id="id_form-0-last_name" maxlength="20" name="form-0-last_name" type="text" value="{{ last_name }}" />
        <p><label for="id_form-1-first_name">First Name:</label>
        <input id="id_form-1-first_name" maxlength="20" name="form-1-first_name" type="text" value="{{ first_name }}" />
        <label for="id_form-1-last_name">Last Name:</label>
        <input id="id_form-1-last_name" maxlength="20" name="form-1-last_name" type="text" value="{{ last_name }}" /></p>
        <p><input type="submit" value="Add Name"></p>
    </form>

    {% if formset.errors %}
    <p style="color: red;">Please correct the error below:</p>
    {{ formset.non_form_errors }}
    {% endif %}

</body>
</html>

在Shell中：

>>> partial_data = {
...     'form-TOTAL_FORMS': '2',
...     'form-INITIAL_FORMS': '0',
...     'form-MAX_NUM_FORMS': '3',
...     'form-0-first_name': 'John',
...     'form-0-last_name': 'Doe',
...     'form-1-first_name': 'James',
...     'form-1-last_name': ''
... }
>>> 
>>> NameFormSet = formset_factory (NameForm, formset = BaseNameFormSet)
>>> formset = NameFormSet (partial_data)
>>> 
>>> formset.is_valid ()
False
>>> formset.errors
[{}, {}]
>>> formset.non_form_errors ()
['Both first and last name must be filled out']

Answer 1

表单集与表单完全相同，只需将其与request.POST一起加载即可。

这是我的一个项目中的一些代码。

formset = modelformset_factory(PaymentTemplates, extra=extras, form=PaymentTemplateForm)
    if request.POST:
        formset = formset(request.POST)

在您的模板中：

{% if formset.total_error_count %}
    <ul class="errorList">
    {% for dict in formset.errors %}
        {% for error in dict.values %}
        <li>{{ error }}</li>
        {% endfor %}
    {% endfor %}
    </ul>
{% endif %}

我想你也知道你需要这个：

<form action="..." method="POST">
{% csrf_token %}
{{ formset.management_form }}
{% for form in formset %}
    {{ form.as_table }}
{% endfor %}
</form>

查找如何手动呈现表单，或使用诸如脆皮表单或带有模板标签的django-bootstrap3之类的东西来处理所有这些。

Answer 2

事实证明，我需要在下面进行更改。 此处的关键是将“ first_name_0”变量与html中的“ form-0-first_name”输入字段相关联。 如果使变量和html输入框的名称相同，则会出现错误。

例如：

return render (request, 'nameform/addname.html', {
        'formset': formset,
        'form-0-first_name': request.POST.get ('form-0-first_name', '')})

Django不喜欢这种格式。 而是使其与下面的内容相同，以将哪个输入字段与变量匹配。

views.py

...
...
...
    return render (request, 'nameform/addname.html', {
        'formset': formset,
        'first_name_0': request.POST.get ('form-0-first_name', ''),
        'last_name_0': request.POST.get ('form-0-last_name', ''),
        'first_name_1': request.POST.get ('form-1-first_name', ''),
        'last_name_1': request.POST.get ('form-1-last_name', '')

addname.hmtl

   ...
    ...
    ...
    {{ formset.management_form }}
            <label for="id_form-0-first_name">First Name:</label>
            <input id="id_form-0-first_name" maxlength="20" name="form-0-first_name" type="text" value="{{ first_name_0 }}" />
            <label for="id_form-0-last_name">Last Name:</label>
            <input id="id_form-0-last_name" maxlength="20" name="form-0-last_name" type="text" value="{{ last_name_0 }}" />
            <p><label for="id_form-1-first_name">First Name:</label>
            <input id="id_form-1-first_name" maxlength="20" name="form-1-first_name" type="text" value="{{ first_name_1 }}" />
            <label for="id_form-1-last_name">Last Name:</label>
            <input id="id_form-1-last_name" maxlength="20" name="form-1-last_name" type="text" value="{{ last_name_1 }}" /></p>

预期结果：

现在，用户无需重新填写整个表格即可知道他们做错了什么或缺少了什么。