Django表单processing

Django表单overview

表单 is Webapplicationin用于收集user输入 important component. Djangoproviding了强 big 表单processingfunctions, including表单class定义, 表单verification, 表单渲染etc..

表单class

in Djangoin, 表单 is throughPythonclass来定义 , inheritance自django.forms.Formclass.

creation表单class

# blog/forms.py
from django import forms

class CommentForm(forms.Form):
    name = forms.CharField(label='姓名', max_length=100)
    email = forms.EmailField(label='邮箱')
    content = forms.CharField(label='评论 in 容', widget=forms.Textarea)
    
    # 自定义verificationmethod
    def clean_name(self):
        name = self.cleaned_data.get('name')
        if len(name) < 2:
            raise forms.ValidationError('姓名 long 度不能 few 于2个字符')
        return name

常用表单字段class型

• CharField: 文本输入框, 用于接收 short 文本.
• TextField: many 行文本输入框, 用于接收 long 文本.
• EmailField: 邮箱输入框, 会自动verification邮箱格式.
• URLField: URL输入框, 会自动verificationURL格式.
• IntegerField: 整数输入框.
• FloatField: 浮点数输入框.
• DecimalField: 十进制 small 数输入框.
• BooleanField: 复选框, 用于接收boolean值.
• DateField: 日期输入框.
• DateTimeField: 日期时间输入框.
• ChoiceField: under 拉选择框, 用于 from 预定义选项in选择.
• MultipleChoiceField: many 选框, 用于 from 预定义选项in选择 many 个.
• FileField: file on 传字段.
• ImageField: graph片 on 传字段, 会自动verificationgraph片格式.

表单字段选项

• label: 表单字段 tag文本.
• required: is 否 for 必填字段, 默认 for True.
• max_length: 最 big long 度.
• min_length: 最 small long 度.
• initial: 初始值.
• help_text: helping文本, 显示 in 字段 under 方.
• widget: 表单字段 HTML部件, 用于自定义字段 渲染方式.
• validators: 自定义verification器list.

in 视graphinusing表单

in 视graphin, 需要creation表单instance, 并processing表单 submitting and verification.

# blog/views.py
from django.shortcuts import render, get_object_or_404
from .models import BlogPost, Comment
from .forms import CommentForm

def post_detail(request, pk):
    post = get_object_or_404(BlogPost, pk=pk)
    comments = post.comments.all()
    
    if request.method == 'POST':
        # creation表单instance并填充data
        form = CommentForm(request.POST)
        if form.is_valid():
            # 获取verification after  data
            cleaned_data = form.cleaned_data
            # creation评论object
            comment = Comment(
                post=post,
                name=cleaned_data['name'],
                email=cleaned_data['email'],
                content=cleaned_data['content']
            )
            comment.save()
            # 重定向 to 当 before 页面, 避免表单重复submitting
            return redirect('post_detail', pk=pk)
    else:
        # creation空表单instance
        form = CommentForm()
    
    return render(request, 'blog/post_detail.html', {
        'post': post,
        'comments': comments,
        'form': form
    })

in 模板in渲染表单

Djangoproviding了 many 种方式 in 模板in渲染表单.

自动渲染表单

<!-- 渲染整个表单 -->
<form method="post">
    {% csrf_token %}
    {{ form.as_p }}  <!-- 每个字段serving asptag -->
    <!-- other渲染方式: 
    {{ form.as_table }}  <!-- 每个字段serving astable行 -->
    {{ form.as_ul }}     <!-- 每个字段serving asullist项 -->
    -->
    <button type="submit">submitting评论</button>
</form>

手动渲染表单字段

<form method="post">
    {% csrf_token %}
    
    <div class="form-group">
        <label for="{{ form.name.id_for_label }}">{{ form.name.label }}</label>
        {{ form.name }}  <!-- 渲染单个字段 -->
        {% if form.name.errors %}
            <div class="error">{{ form.name.errors }}</div>
        {% endif %}
        <small class="help-text">{{ form.name.help_text }}</small>
    </div>
    
    <div class="form-group">
        <label for="{{ form.email.id_for_label }}">{{ form.email.label }}</label>
        {{ form.email }}
        {% if form.email.errors %}
            <div class="error">{{ form.email.errors }}</div>
        {% endif %}
    </div>
    
    <div class="form-group">
        <label for="{{ form.content.id_for_label }}">{{ form.content.label }}</label>
        {{ form.content }}
        {% if form.content.errors %}
            <div class="error">{{ form.content.errors }}</div>
        {% endif %}
    </div>
    
    <button type="submit">submitting评论</button>
</form>

表单errorprocessing

<!-- 显示表单 非字段error -->
{% if form.non_field_errors %}
    <div class="error">{{ form.non_field_errors }}</div>
{% endif %}

ModelForm

ModelForm is Djangoproviding 一个强 big functions, 它可以根据model自动生成表单.

creationModelForm

# blog/forms.py
from django import forms
from .models import BlogPost

class BlogPostForm(forms.ModelForm):
    class Meta:
        model = BlogPost
        fields = ['title', 'content', 'is_published']  # 指定要package含 字段
        #  or 者排除某些字段
        # exclude = ['pub_date', 'update_date']
        
        # 自定义字段tag and helping文本
        labels = {
            'title': '文章标题',
            'content': '文章 in 容',
            'is_published': ' is 否release'
        }
        help_texts = {
            'title': '请输入文章标题',
            'content': '请输入文章 in 容',
            'is_published': '勾选表示release这篇文章'
        }
        # 自定义widget
        widgets = {
            'content': forms.Textarea(attrs={'rows': 10, 'cols': 80})
        }

in 视graphinusingModelForm

# blog/views.py
from django.shortcuts import render, redirect
from .forms import BlogPostForm

def create_post(request):
    if request.method == 'POST':
        form = BlogPostForm(request.POST)
        if form.is_valid():
            # 保存表单data to datalibrary
            form.save()
            return redirect('post_list')
    else:
        form = BlogPostForm()
    
    return render(request, 'blog/create_post.html', {'form': form})

# update文章
def update_post(request, pk):
    post = get_object_or_404(BlogPost, pk=pk)
    if request.method == 'POST':
        form = BlogPostForm(request.POST, instance=post)  # 传入instanceparameter表示update现 has object
        if form.is_valid():
            form.save()
            return redirect('post_detail', pk=pk)
    else:
        form = BlogPostForm(instance=post)  # 传入instanceparameter表示using现 has object data填充表单
    
    return render(request, 'blog/update_post.html', {'form': form, 'post': post})

ModelForm模板

<!-- blog/templates/blog/create_post.html -->
{% extends 'blog/base.html' %}

{% block title %}creation文章{% endblock %}

{% block content %}
    <h1>creation new 文章</h1>
    <form method="post">
        {% csrf_token %}
        {{ form.as_p }}
        <button type="submit">creation文章</button>
    </form>
{% endblock %}

表单verification

Django表单systemproviding了强 big verificationfunctions, including字段级verification and 表单级verification.

字段级verification

through in 表单classin定义clean_字段名method来implementation字段级verification:

def clean_email(self):
    email = self.cleaned_data.get('email')
    if '@example.com' in email:
        raise forms.ValidationError('不允许usingexample.com邮箱')
    return email

表单级verification

through重写表单class cleanmethod来implementation表单级verification:

def clean(self):
    cleaned_data = super().clean()
    password1 = cleaned_data.get('password1')
    password2 = cleaned_data.get('password2')
    
    if password1 and password2 and password1 != password2:
        raise forms.ValidationError('两次输入 password不一致')
    
    return cleaned_data

表单样式定制

可以through自定义widget attrsproperty来添加CSSclass and otherHTMLproperty:

# 方式1:  in 表单classin定义
class CommentForm(forms.Form):
    name = forms.CharField(
        label='姓名', 
        max_length=100,
        widget=forms.TextInput(attrs={'class': 'form-control', 'placeholder': '请输入姓名'})
    )
    # other字段...

# 方式2:  in 视graphin动态添加
form = CommentForm()
form.fields['name'].widget.attrs.update({'class': 'form-control'})
form.fields['email'].widget.attrs.update({'class': 'form-control'})
form.fields['content'].widget.attrs.update({'class': 'form-control', 'rows': 5})