form组件相关 -新 -转

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2024-10-17 08:46:38 216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>

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

其他标签有

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

   >>> import uuid

    # make a UUID based on the host ID and current time
    >>> uuid.uuid1()    # doctest: +SKIP
    UUID(‘a8098c1a-f86e-11da-bd1a-00112444be1e‘)

    # make a UUID using an MD5 hash of a namespace UUID and a name
    >>> uuid.uuid3(uuid.NAMESPACE_DNS, ‘python.org‘)
    UUID(‘6fa459ea-ee8a-3ca4-894e-db77e160355e‘)

    # make a random UUID
    >>> uuid.uuid4()    # doctest: +SKIP
    UUID(‘16fd2706-8baf-433b-82eb-8c7fada847da‘)

    # make a UUID using a SHA-1 hash of a namespace UUID and a name
    >>> uuid.uuid5(uuid.NAMESPACE_DNS, ‘python.org‘)
    UUID(‘886313e1-3b8a-5372-9b90-0c9aee199e5d‘)

    # make a UUID from a string of hex digits (braces and hyphens ignored)
    >>> x = uuid.UUID(‘{00010203-0405-0607-0809-0a0b0c0d0e0f}‘)

    # convert a UUID to a string of hex digits in standard form
    >>> str(x)
    ‘00010203-0405-0607-0809-0a0b0c0d0e0f‘

    # get the raw 16 bytes of the UUID
    >>> x.bytes
    b‘\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f‘

    # make a UUID from a 16-byte string
    >>> uuid.UUID(bytes=x.bytes)
    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>

form组件相关 -新 -转

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