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📜  error_messages – Django 表单字段验证

📅  最后修改于: 2022-05-13 01:54:46.588000             🧑  作者: Mango

error_messages – Django 表单字段验证

Django 表单中的内置表单字段验证是为所有字段预定义的默认验证。每个字段都带有来自 Django 验证器的一些内置验证。每个 Field 类的构造函数都有一些固定的参数。

error_messages参数允许您为字段的属性指定手动错误消息。 error_messages 参数允许您覆盖该字段将引发的默认消息。传入带有与您要覆盖的错误消息匹配的键的字典。例如，这是默认的错误消息： 

>>> from django import forms
>>> generic = forms.CharField()
>>> generic.clean('')
Traceback (most recent call last):
  ...
ValidationError: ['This field is required.']

这是一条自定义错误消息： 

>>> name = forms.CharField(
                error_messages={
               'required': 'Please enter your name'
                })
>>> name.clean('')
Traceback (most recent call last):
  ...
ValidationError: ['Please enter your name']

句法

field_name = models.Field(option = value)

Django 表单字段验证error_messages解释

使用示例说明 error_messages。考虑一个名为geeks的项目，它有一个名为geeksforgeeks的应用程序。

在geeks app的forms.py文件中输入以下代码。我们将使用 CharField 来试验所有字段选项。 

from django import forms
  
class GeeksForm(forms.Form):
    geeks_field = forms.CharField(
                  error_messages = {
                 'required':"Please Enter your Name"
                 })

将极客应用添加到INSTALLED_APPS 

# Application definition
  
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'geeks',
]

现在要将这个表单渲染到一个视图中，我们需要一个视图和一个映射到该视图的 URL。我们先在geeks app的views.py中创建一个视图， 

from django.shortcuts import render
from .forms import GeeksForm
  
# Create your views here.
def home_view(request):
    context = {}
    form = GeeksForm(request.POST or None)
    context['form'] = form
    if request.POST:
        if form.is_valid():
            temp = form.cleaned_data.get("geeks_field")
            print(temp)
    return render(request, "home.html", context)

在这里，我们从 forms.py 导入该特定表单并在视图中创建它的对象，以便可以在模板中呈现它。
现在，要启动一个 Django 表单，您需要创建 home.html，在其中可以根据需要设计内容。让我们在home.html中创建一个表单。 


    {% csrf_token %}
    {{ form }}
    

最后，在 urls.py 中映射到该视图的 URL 

from django.urls import path
  
# importing views from views..py
from .views import home_view
  
URLpatterns = [
    path('', home_view ),
]

让我们运行服务器并检查实际发生了什么，运行

Python manage.py runserver

error_messages - Django 表单字段验证

现在让我们尝试将其提交为空并检查是否已覆盖所需的error_message 。

error_messages-Django-Form-Field-Validation

因此，该字段为 Charfield 的required属性显示自定义错误消息。

更多内置表单验证

Field OptionsDescription
requiredBy default, each Field class assumes the value is required, so to make it not required you need to set required=False
labelThe label argument lets you specify the “human-friendly” label for this field. This is used when the Field is displayed in a Form.
label_suffixThe label_suffix argument lets you override the form’s label_suffix on a per-field basis.
widgetThe widget argument lets you specify a Widget class to use when rendering this Field. See Widgets for more information.
help_textThe help_text argument lets you specify descriptive text for this Field. If you provide help_text, it will be displayed next to the Field when the Field is rendered by one of the convenience Form methods.
error_messagesThe error_messages argument lets you override the default messages that the field will raise. Pass in a dictionary with keys matching the error messages you want to override.
validatorsThe validators argument lets you provide a list of validation functions for this field.
localizeThe localize argument enables the localization of form data input, as well as the rendered output.
disabled.The disabled boolean argument, when set to True, disables a form field using the disabled HTML attribute so that it won’t be editable by users.