如何在模板中显示Django表单字段的值？ [英] How do I display the value of a Django form field in a template?

问题描述

我有一个带有电子邮件属性的表单。

I have a form with an email property.

在 {{form.email}} 中使用时在出现某些验证错误的情况下，Django仍会在输入标签的value属性中呈现先前的值：

When using {{ form.email }} in case of some validation error, Django still renders the previous value in the input tag's value attribute:

<input type="text" id="id_email" maxlength="75" class="required"
       value="[e-mail]" name="email">

我想自己渲染输入标签（以添加一些JavaScript代码和错误类）一个错误）。例如，这是我的模板，而不是 {{form.email}} ：

I want to render the input tag myself (to add some JavaScript code and an error class in case of an error). For example this is my template instead of {{ form.email }}:

<input type="text" autocomplete="on" id="id_email" name="email"
       class="email {% if form.email.errors %} error {% endif %}">

但是，这不会显示错误的值（ [e-mail] ））

However, this does not display the erroneous value ([e-mail] in this example) to the user.

如何在模板中获取字段的值？

How do I get the field's value in the template?

推荐答案

Jens提出的解决方案是正确的。
但是，事实证明，如果使用 instance （下面的示例）初始化ModelForm，django将不会填充数据：

The solution proposed by Jens is correct. However, it turns out that if you initialize your ModelForm with an instance (example below) django will not populate the data:

def your_view(request):   
    if request.method == 'POST':
        form = UserDetailsForm(request.POST)
        if form.is_valid():
          # some code here   
        else:
          form = UserDetailsForm(instance=request.user)

因此，我制作了自己的ModelForm基类，用于填充初始数据：

So, I made my own ModelForm base class that populates the initial data:

from django import forms 
class BaseModelForm(forms.ModelForm):
    """
    Subclass of `forms.ModelForm` that makes sure the initial values
    are present in the form data, so you don't have to send all old values
    for the form to actually validate.
    """
    def merge_from_initial(self):
        filt = lambda v: v not in self.data.keys()
        for field in filter(filt, getattr(self.Meta, 'fields', ())):
            self.data[field] = self.initial.get(field, None)

然后，简单视图示例如下：

Then, the simple view example looks like this:

def your_view(request):   if request.method == 'POST':
    form = UserDetailsForm(request.POST)
    if form.is_valid():
      # some code here   
    else:
      form = UserDetailsForm(instance=request.user)
      form.merge_from_initial()

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