Django之Form组件

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2024-09-14 00:26:16 218人阅读

Django的Form主要具有一下几大功能：

生成HTML标签
验证用户数据（显示错误信息）
HTML Form提交保留上次提交数据
初始化页面显示内容

小试牛刀

1、创建Form类

from django.forms import Form
from django.forms import widgets
from django.forms import fields
 
class MyForm(Form):
    user = fields.CharField(
        widget=widgets.TextInput(attrs={‘id‘: ‘i1‘, ‘class‘: ‘c1‘})
    )
 
    gender = fields.ChoiceField(
        choices=((1, ‘男‘), (2, ‘女‘),),
        initial=2,
        widget=widgets.RadioSelect
    )
 
    city = fields.CharField(
        initial=2,
        widget=widgets.Select(choices=((1,‘上海‘),(2,‘北京‘),))
    )
 
    pwd = fields.CharField(
        widget=widgets.PasswordInput(attrs={‘class‘: ‘c1‘}, render_value=http://www.mamicode.com/True)>

　　2、View函数处理

from django.shortcuts import render, redirect
from .forms import MyForm
 
 
def index(request):
    if request.method == "GET":
        obj = MyForm()
        return render(request, ‘index.html‘, {‘form‘: obj})
    elif request.method == "POST":
        obj = MyForm(request.POST, request.FILES)
        if obj.is_valid():
            values = obj.clean()
            print(values)
        else:
            errors = obj.errors
            print(errors)
        return render(request, ‘index.html‘, {‘form‘: obj})
    else:
        return redirect(‘http://www.google.com‘)

　　3、生成HTML

<form action="/" method="POST" enctype="multipart/form-data">
    <p>{{ form.user }} {{ form.user.errors }}</p>
    <p>{{ form.gender }} {{ form.gender.errors }}</p>
    <p>{{ form.city }} {{ form.city.errors }}</p>
    <p>{{ form.pwd }} {{ form.pwd.errors }}</p>
    <input type="submit"/>
</form>

 1 <form method="POST" enctype="multipart/form-data">
 2         {% csrf_token %}
 3         
 4             {{ form.xxoo.label }}
 5             {{ form.xxoo.id_for_label }}
 6             {{ form.xxoo.label_tag }}
 7             {{ form.xxoo.errors }}
 8             <p>{{ form.user }} {{ form.user.errors }}</p>
 9             <input type="submit" />
10     </form>

其他标签

Form类

创建Form类时，主要涉及到【字段】和【插件】，字段用于对用户请求数据的验证，插件用于自动生成HTML;

1、Django内置字段如下：

Field
    required=True,               是否允许为空
    widget=None,                 HTML插件
    label=None,                  用于生成Label标签或显示内容
    initial=None,                初始值
    help_text=‘‘,                帮助信息(在标签旁边显示)
    error_messages=None,         错误信息 {‘required‘: ‘不能为空‘, ‘invalid‘: ‘格式错误‘}
    show_hidden_initial=False,   是否在当前插件后面再加一个隐藏的且具有默认值的插件（可用于检验两次输入是否一直）
    validators=[],               自定义验证规则
    localize=False,              是否支持本地化
    disabled=False,              是否可以编辑
    label_suffix=None            Label内容后缀
 
 
CharField(Field)
    max_length=None,             最大长度
    min_length=None,             最小长度
    strip=True                   是否移除用户输入空白
 
IntegerField(Field)
    max_value=http://www.mamicode.com/None,              最大值"multipart/form-data"
        - view函数中 obj = MyForm(request.POST, request.FILES)
 
URLField(Field)
    ...
 
 
BooleanField(Field)  
    ...
 
NullBooleanField(BooleanField)
    ...
 
ChoiceField(Field)
    ...
    choices=(),                选项，如：choices = ((0,‘上海‘),(1,‘北京‘),)
    required=True,             是否必填
    widget=None,               插件，默认select插件
    label=None,                Label内容
    initial=None,              初始值
    help_text=‘‘,              帮助提示
 
 
ModelChoiceField(ChoiceField)
    ...                        django.forms.models.ModelChoiceField
    queryset,                  # 查询数据库中的数据
    empty_label="---------",   # 默认空显示内容
    to_field_name=None,        # HTML中value的值对应的字段
    limit_choices_to=None      # ModelForm中对queryset二次筛选
     
ModelMultipleChoiceField(ModelChoiceField)
    ...                        django.forms.models.ModelMultipleChoiceField
 
 
     
TypedChoiceField(ChoiceField)
    coerce = lambda val: val   对选中的值进行一次转换
    empty_value= http://www.mamicode.com/‘‘            空值的默认值>

　　注：UUID是根据MAC以及当前时间等创建的不重复的随机字符串

 1 >>> import uuid
 2 
 3     # make a UUID based on the host ID and current time
 4     >>> uuid.uuid1()    # doctest: +SKIP
 5     UUID(‘a8098c1a-f86e-11da-bd1a-00112444be1e‘)
 6 
 7     # make a UUID using an MD5 hash of a namespace UUID and a name
 8     >>> uuid.uuid3(uuid.NAMESPACE_DNS, ‘python.org‘)
 9     UUID(‘6fa459ea-ee8a-3ca4-894e-db77e160355e‘)
10 
11     # make a random UUID
12     >>> uuid.uuid4()    # doctest: +SKIP
13     UUID(‘16fd2706-8baf-433b-82eb-8c7fada847da‘)
14 
15     # make a UUID using a SHA-1 hash of a namespace UUID and a name
16     >>> uuid.uuid5(uuid.NAMESPACE_DNS, ‘python.org‘)
17     UUID(‘886313e1-3b8a-5372-9b90-0c9aee199e5d‘)
18 
19     # make a UUID from a string of hex digits (braces and hyphens ignored)
20     >>> x = uuid.UUID(‘{00010203-0405-0607-0809-0a0b0c0d0e0f}‘)
21 
22     # convert a UUID to a string of hex digits in standard form
23     >>> str(x)
24     ‘00010203-0405-0607-0809-0a0b0c0d0e0f‘
25 
26     # get the raw 16 bytes of the UUID
27     >>> x.bytes
28     b‘\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f‘
29 
30     # make a UUID from a 16-byte string
31     >>> uuid.UUID(bytes=x.bytes)
32     UUID(‘00010203-0405-0607-0809-0a0b0c0d0e0f‘)

View Code

2、Django内置插件：

TextInput(Input)
NumberInput(TextInput)
EmailInput(TextInput)
URLInput(TextInput)
PasswordInput(TextInput)
HiddenInput(TextInput)
Textarea(Widget)
DateInput(DateTimeBaseInput)
DateTimeInput(DateTimeBaseInput)
TimeInput(DateTimeBaseInput)
CheckboxInput
Select
NullBooleanSelect
SelectMultiple
RadioSelect
CheckboxSelectMultiple
FileInput
ClearableFileInput
MultipleHiddenInput
SplitDateTimeWidget
SplitHiddenDateTimeWidget
SelectDateWidget

常用选择插件

# 单radio，值为字符串
# user = fields.CharField(
#     initial=2,
#     widget=widgets.RadioSelect(choices=((1,‘上海‘),(2,‘北京‘),))
# )
 
# 单radio，值为字符串
# user = fields.ChoiceField(
#     choices=((1, ‘上海‘), (2, ‘北京‘),),
#     initial=2,
#     widget=widgets.RadioSelect
# )
 
# 单select，值为字符串
# user = fields.CharField(
#     initial=2,
#     widget=widgets.Select(choices=((1,‘上海‘),(2,‘北京‘),))
# )
 
# 单select，值为字符串
# user = fields.ChoiceField(
#     choices=((1, ‘上海‘), (2, ‘北京‘),),
#     initial=2,
#     widget=widgets.Select
# )
 
# 多选select，值为列表
# user = fields.MultipleChoiceField(
#     choices=((1,‘上海‘),(2,‘北京‘),),
#     initial=[1,],
#     widget=widgets.SelectMultiple
# )
 
 
# 单checkbox
# user = fields.CharField(
#     widget=widgets.CheckboxInput()
# )
 
 
# 多选checkbox,值为列表
# user = fields.MultipleChoiceField(
#     initial=[2, ],
#     choices=((1, ‘上海‘), (2, ‘北京‘),),
#     widget=widgets.CheckboxSelectMultiple
# )

在使用选择标签时，需要注意choices的选项可以从数据库中获取，但是由于是静态字段 ***获取的值无法实时更新***，那么需要自定义构造方法从而达到此目的。

方式一：

from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
 
class MyForm(Form):
 
    user = fields.ChoiceField(
        # choices=((1, ‘上海‘), (2, ‘北京‘),),
        initial=2,
        widget=widgets.Select
    )
 
    def __init__(self, *args, **kwargs):
        super(MyForm,self).__init__(*args, **kwargs)
        # self.fields[‘user‘].widget.choices = ((1, ‘上海‘), (2, ‘北京‘),)
        # 或
        self.fields[‘user‘].widget.choices = models.Classes.objects.all().value_list(‘id‘,‘caption‘)

方式二：

使用django提供的ModelChoiceField和ModelMultipleChoiceField字段来实现

from django import forms
from django.forms import fields
from django.forms import widgets
from django.forms import models as form_model
from django.core.exceptions import ValidationError
from django.core.validators import RegexValidator
 
class FInfo(forms.Form):
    authors = form_model.ModelMultipleChoiceField(queryset=models.NNewType.objects.all())
    # authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all())

自定义验证规则

方式一：

from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
 
class MyForm(Form):
    user = fields.CharField(
        validators=[RegexValidator(r‘^[0-9]+$‘, ‘请输入数字‘), RegexValidator(r‘^159[0-9]+$‘, ‘数字必须以159开头‘)],
    )

　　方式二：

import re
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.exceptions import ValidationError
 
 
# 自定义验证规则
def mobile_validate(value):
    mobile_re = re.compile(r‘^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$‘)
    if not mobile_re.match(value):
        raise ValidationError(‘手机号码格式错误‘)
 
 
class PublishForm(Form):
 
 
    title = fields.CharField(max_length=20,
                            min_length=5,
                            error_messages={‘required‘: ‘标题不能为空‘,
                                            ‘min_length‘: ‘标题最少为5个字符‘,
                                            ‘max_length‘: ‘标题最多为20个字符‘},
                            widget=widgets.TextInput(attrs={‘class‘: "form-control",
                                                          ‘placeholder‘: ‘标题5-20个字符‘}))
 
 
    # 使用自定义验证规则
    phone = fields.CharField(validators=[mobile_validate, ],
                            error_messages={‘required‘: ‘手机不能为空‘},
                            widget=widgets.TextInput(attrs={‘class‘: "form-control",
                                                          ‘placeholder‘: u‘手机号码‘}))
 
    email = fields.EmailField(required=False,
                            error_messages={‘required‘: u‘邮箱不能为空‘,‘invalid‘: u‘邮箱格式错误‘},
                            widget=widgets.TextInput(attrs={‘class‘: "form-control", ‘placeholder‘: u‘邮箱‘}))

　　方法三：自定义方法

from django import forms
    from django.forms import fields
    from django.forms import widgets
    from django.core.exceptions import ValidationError
    from django.core.validators import RegexValidator
 
    class FInfo(forms.Form):
        username = fields.CharField(max_length=5,
                                    validators=[RegexValidator(r‘^[0-9]+$‘, ‘Enter a valid extension.‘, ‘invalid‘)], )
        email = fields.EmailField()
 
        def clean_username(self):
            """
            Form中字段中定义的格式匹配完之后，执行此方法进行验证
            :return:
            """
            value = http://www.mamicode.com/self.cleaned_data[‘username‘]"666" in value:
                raise ValidationError(‘666已经被玩烂了...‘, ‘invalid‘)
            return value

　　方式四：同时生成多个标签进行验证

from django.forms import Form
from django.forms import widgets
from django.forms import fields
 
from django.core.validators import RegexValidator
 
 
############## 自定义字段 ##############
class PhoneField(fields.MultiValueField):
    def __init__(self, *args, **kwargs):
        # Define one message for all fields.
        error_messages = {
            ‘incomplete‘: ‘Enter a country calling code and a phone number.‘,
        }
        # Or define a different message for each field.
        f = (
            fields.CharField(
                error_messages={‘incomplete‘: ‘Enter a country calling code.‘},
                validators=[
                    RegexValidator(r‘^[0-9]+$‘, ‘Enter a valid country calling code.‘),
                ],
            ),
            fields.CharField(
                error_messages={‘incomplete‘: ‘Enter a phone number.‘},
                validators=[RegexValidator(r‘^[0-9]+$‘, ‘Enter a valid phone number.‘)],
            ),
            fields.CharField(
                validators=[RegexValidator(r‘^[0-9]+$‘, ‘Enter a valid extension.‘)],
                required=False,
            ),
        )
        super(PhoneField, self).__init__(error_messages=error_messages, fields=f, require_all_fields=False, *args,
                                         **kwargs)
 
    def compress(self, data_list):
        """
        当用户验证都通过后，该值返回给用户
        :param data_list:
        :return:
        """
        return data_list
 
############## 自定义插件 ##############
class SplitPhoneWidget(widgets.MultiWidget):
    def __init__(self):
        ws = (
            widgets.TextInput(),
            widgets.TextInput(),
            widgets.TextInput(),
        )
        super(SplitPhoneWidget, self).__init__(ws)
 
    def decompress(self, value):
        """
        处理初始值，当初始值initial不是列表时，调用该方法
        :param value:
        :return:
        """
        if value:
            return value.split(‘,‘)
        return [None, None, None]

初始化数据

在Web应用程序中开发编写功能时，时常用到获取数据库中的数据并将值初始化在HTML中的标签上。

1、Form

from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
 
 
class MyForm(Form):
    user = fields.CharField()
 
    city = fields.ChoiceField(
        choices=((1, ‘上海‘), (2, ‘北京‘),),
        widget=widgets.Select
    )

2、Views

from django.shortcuts import render, redirect
from .forms import MyForm
 
 
def index(request):
    if request.method == "GET":
        values = {‘user‘: ‘root‘, ‘city‘: 2}
        obj = MyForm(values)
 
        return render(request, ‘index.html‘, {‘form‘: obj})
    elif request.method == "POST":
        return redirect(‘http://www.google.com‘)
    else:
        return redirect(‘http://www.google.com‘)

3、HTML

<form method="POST" enctype="multipart/form-data">
    {% csrf_token %}
    <p>{{ form.user }} {{ form.user.errors }}</p>
    <p>{{ form.city }} {{ form.city.errors }}</p>
 
    <input type="submit"/>
</form>

Django之Form组件

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