Django：如何使用 formset extra 更改标签？

Posted 2023-02-24

【中文标题】Django：如何使用 formset extra 更改标签？

【英文标题】：Django: how to change label using formset extra?

【发布时间】：2013-01-04 09:49:15

【问题描述】：

我使用formset生成额外字段，但我不知道如何更改formset生成的额外字段的标签。

我的代码：

class GetMachine(forms.Form):
    Number_of_Lines = forms.IntegerField(max_value=4)

class GetLine(forms.Form):
    beamline_name = forms.CharField(max_length=15, label='Name of Beamline-%i')

def install(request):
    MachineFormSet = formset_factory(GetMachine, extra=1)
    formset = MachineFormSet()
    if request.method == 'POST':
#        formset = MachineFormSet(request.POST) 
#        if formset.is_valid(): # All validation rules pass
        line_no = request.POST['form-0-Number_of_Lines']
        GetLineFormSet = formset_factory(GetLine, extra=int(line_no))
        formset = GetLineFormSet()
        return render_to_response('install.html',  'formset': formset, 'action': 'step1')
    return render_to_response('install.html',  'formset': formset, )    

install.html 模板：

% for form in formset.forms %
% for field in form %
    <tr>
        <td> field.label_tag </td>  <td> field </td><td> field.errors </td>
    </tr>
% endfor %
% endfor %

例如，如果 "Number_of_Lines" = 2，那么我期望下一个带有标签的表单，

Name of Beamline-1:
Name of Beamline-2:

【参考方案1】：

我假设您希望第一个表单的结果确定第二个表单的字段数及其标签，您可能需要查看Django form wizards。但这是一种简单的非表单向导（可能不太理想/可维护）的方法，利用表单集的__init__ 方法来修改表单标签*：

---

forms.py：

# File: forms.py
from django import forms
from django.forms.formsets import BaseFormSet


# What you've called 'GetMachine'
class MachineForm(forms.Form):
    no_of_lines = forms.IntegerField(max_value=4)


# What you've called 'GetLine'
class LineForm(forms.Form):
    beamline_name = forms.CharField(max_length=15, label='Name of Beamline')


# Create a custom formset and override __init__
class BaseLineFormSet(BaseFormSet):
    def __init__(self, *args, **kwargs):
        super(BaseLineFormSet, self).__init__(*args, **kwargs)
        no_of_forms = len(self)
        for i in range(0, no_of_forms):
            self[i].fields['beamline_name'].label += "-%d" % (i + 1)

views.py：

# File: views.py
from django.forms.formsets import formset_factory
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.http import HttpResponseRedirect
from django.core.urlresolvers import reverse
from forms import MachineForm, LineForm, BaseLineFormSet


def get_no_of_lines(request):
    if request.method == 'POST':
        machine_form = MachineForm(request.POST)
        if machine_form.is_valid():
            # At this point, form fields have already been 
            # converted to Python data types :)
            # so no need to convert `line_no` to an integer
            no_of_lines = machine_form.cleaned_data['no_of_lines']
            return HttpResponseRedirect(reverse('line_form', kwargs='no_of_lines': no_of_lines))
    else:
        # It looks to me like you probably don't mean to
        # use formsets here (but a form instead)
        machine_form = MachineForm()

    c = RequestContext(request, 
        'machine_form': machine_form,
    )
    return render_to_response('get_no_of_lines.html', c)


def line_form(request, no_of_lines):
    # You probably should validate this number (again).
    # In fact, you probably need to validate first form (MachineForm).
    # ...But I'm assuming it'll be valid in this example.
    no_of_lines = int(no_of_lines)
    LineFormSet = formset_factory(LineForm, extra=no_of_lines, formset=BaseLineFormSet)
    if request.method == "POST":
        formset = LineFormSet(request.POST, request.FILES)
        if formset.is_valid():
            pass
            # Do stuff with form submission
            # Redirect

    else:
        formset = LineFormSet()

    c = RequestContext(request, 
        'formset': formset,
    )
    return render_to_response('line_form.html', c)

urls.py:

from django.conf.urls import url, patterns
from views import get_no_of_lines, line_form


urlpatterns = patterns('',
     url(r'^$', get_no_of_lines, name='get_no_of_lines'),
     url(r'^line_form/(?P<no_of_lines>\d1)$', line_form, name='line_form'),
)

get_no_of_lines.html：

<form method="POST">
% csrf_token %
 machine_form 
</form>

line_form.html：

<form method="POST">
% csrf_token %
 formset.as_p 

---

我之所以说这种方法可能不是最好的方法是因为你必须验证 no_of_lines 被传递给 line_form 视图（可能 > 4，所以你必须执行验证在这里并介绍验证逻辑，而不是把它放在一个地方——表单）。如果您需要在第一个表单中添加一个新字段，您可能最终不得不修改代码。因此，为什么我建议您查看form wizards。

---

如需更多或动态表单，请查看Jacob Kaplan-Moss's post on dynamic form generation。

【参考方案2】：

我能想到的唯一方法是在将 FormSet 传递给您的模板之前在您的视图中调整它。

您可以遍历不同的表单和标签并相应地更改它们的值。

另一种可能的解决方案是将默认标签设置为“光束线名称-”。 在您的模板中执行类似

% for field in form %
    <td> field.label_tag  forloop.counter1 </td> 
% endfor %

【讨论】：

我使用了 counter 它对两个标签都显示 1,1，如果我使用 counter1 没有任何反应，如果我使用 counter0 它对两个标签都显示 0,0。我不明白为什么会这样！