forms组件

Form组件

服务端假设所有用户提交的数据都是不可信任的，所以Django框架内置了form组件来验证用户提交的信息

form组件的2大功能：     

 　　 1 验证（显示错误信息）
 　　 2 保留用户上次输入的信息
         3.可以生成html标签

1 验证（显示错误信息）

示例/:注册用户字段校验

模型：models.py:

class UserInfo(models.Model):
    name=models.CharField(max_length=32)
    pwd=models.CharField(max_length=32)
    email=models.EmailField()
    tel=models.CharField(max_length=32)

模板: register.html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>

<form action="" method="post">
    {% csrf_token %}
    <div>
        <label for="user">用户名</label>
        <p><input type="text" name="name" id="name"></p>
    </div>
    <div>
        <label for="pwd">密码</label>
        <p><input type="password" name="pwd" id="pwd"></p>
    </div>
    <div>
        <label for="r_pwd">确认密码</label>
        <p><input type="password" name="r_pwd" id="r_pwd"></p>
    </div>
     <div>
        <label for="email">邮箱</label>
        <p><input type="text" name="email" id="email"></p>
    </div>
    <input type="submit">
</form>

</body>
</html>
View Code

视图函数：register:

# forms组件
from django.forms import widgets

wid_01=widgets.TextInput(attrs={"class":"form-control"})
wid_02=widgets.PasswordInput(attrs={"class":"form-control"})

class UserForm(forms.Form):
    name=forms.CharField(max_length=32,
                         widget=wid_01
                         )
    pwd=forms.CharField(max_length=32,widget=wid_02)
    r_pwd=forms.CharField(max_length=32,widget=wid_02)
    email=forms.EmailField(widget=wid_01)
    tel=forms.CharField(max_length=32,widget=wid_01)



def register(request):

    if request.method=="POST":
        form=UserForm(request.POST)
        if form.is_valid():
            print(form.cleaned_data)       # 所有干净的字段以及对应的值
        else:
            print(form.cleaned_data)       #
            print(form.errors)             # ErrorDict : {"校验错误的字段":["错误信息",]}
            print(form.errors.get("name")) # ErrorList ["错误信息",]
        return HttpResponse("OK")
    form=UserForm()
    return render(request,"register.html",locals())
View Code

其中视图函数中关于Widgets的详细使用,可参考:http://www.liujiangblog.com/course/django/155

2.   -- 可以生成html标签

生成HTML 标签有三种渲染方式

1. 渲染成文字段落as_p()

Form.as_p()

该方法将form渲染成一系列<p>标签，每个<p>标签包含一个字段；

<form action="" method="post">
    {% csrf_token %}
    
    {{ form.as_p }}
    <input type="submit" class="btn btn-default pull-right">

</form>

2.渲染方式二循环form表单,利用字段:

rm action="" method="post">
    {% csrf_token %}
    {% for field in form %}
        <div>
            <label for="">{{ field.label }}</label>
            {{ field }}
        </div>
    {% endfor %}
    <input type="submit" class="btn btn-default pull-right">
</form>

3.渲染方式三:

<form action="" method="post">
        {% csrf_token %}
        <div>
            <label for="">用户名</label>
            {{ form.name }}
        </div>
        <div>
            <label for="">密码</label>
            {{ form.pwd }}
        </div>
        <div>
            <label for="">确认密码</label>
            {{ form.r_pwd }}
        </div>
        <div>
            <label for=""> 邮箱</label>
            {{ form.email }}
        </div>

        <input type="submit" class="btn btn-default pull-right">
</form>
View Code

3.返回并在界面表示错误

HTML示例:

<form action="" method="post" novalidate>
    {% csrf_token %}
    
    {% for field in form %}
        <div>
            <label for="">{{ field.label }}</label>
            {{ field }} <span class="pull-right" style="color: red">{{ field.errors.0 }}</span>
        </div>
    {% endfor %}
    <input type="submit" class="btn btn-default">

</form>

增加全局钩子和局部钩子的代码示例:

views:

from django.shortcuts import render,HttpResponse
from django import forms
# Create your views here.
from django.forms import widgets
from django.core.exceptions import ValidationError

wid_01=widgets.TextInput(attrs={"class":"form-control"})
wid_02=widgets.PasswordInput(attrs={"class":"form-control"})

class UserForm(forms.Form):
    name=forms.CharField(max_length=32,
                         widget=wid_01
                         )
    pwd=forms.CharField(max_length=32,widget=wid_02)
    r_pwd=forms.CharField(max_length=32,widget=wid_02)
    email=forms.EmailField(widget=wid_01)
    tel=forms.CharField(max_length=32,widget=wid_01)

    # 局部钩子
    def clean_name(self):
        val = self.cleaned_data.get("name")
        if not val.isdigit():
            return val
        else:
            raise ValidationError("用户名不能是纯数字!")

    # 全局钩子

    def clean(self):
        pwd = self.cleaned_data.get("pwd")
        r_pwd = self.cleaned_data.get("r_pwd")

        if pwd == r_pwd:
            return self.cleaned_data
        else:
            raise ValidationError('两次密码不一致!')



def register(request):

    if request.method=="POST":
        form=UserForm(request.POST)
        if form.is_valid():
            print(form.cleaned_data)       # 所有干净的字段以及对应的值
        else:
            clean_error = form.errors.get("__all__")
            print(form.cleaned_data)       #
            print(form.errors)             # ErrorDict : {"校验错误的字段":["错误信息",]}
            print(form.errors.get("name")) # ErrorList ["错误信息",]
            return render(request, "register.html", locals())
        return HttpResponse("OK")
    form=UserForm()
    return render(request,"register.html",locals())
View Code

html:

<form action="" method="post" novalidate>
        {% csrf_token %}
        {% for field in form %}
            <div>
                <label for="">{{ field.label }}</label>
                {{ field }}
                <span class="pull-right" style="color: red">
                      {% if field.label == 'R pwd' %}
                      <span>{{ clean_error.0 }}</span>
                      {% endif %}
                      {{ field.errors.0 }}
                </span>
            </div>
        {% endfor %}
        <input type="submit" class="btn btn-default">

</form>
View Code

 

以下几种form表单渲染方式示例,请详看:

# 通过直接form生成的HTML文件如下
# <form action="/name/" method="post">
#     {% csrf_token %}
#     {{ form }}
#     <input type="submit" value="Submit" />
# </form>

# 渲染后:
# <form action="/name/" method="post">
#     <input type="hidden" name="csrfmiddlewaretoken" value="B3iGL11TlxDRrhRhC96iDdQrJSOiUDoU8QYgw1euE2sddZONoAogOnfHJZtgSY0X">
#     <label for="id_subject">Subject:</label><input type="text" name="subject" maxlength="100" required="" id="id_subject">
#     <label for="id_message">Message:</label><textarea name="message" cols="40" rows="10" required="" id="id_message"></textarea>
#     <label for="id_sender">Sender:</label><input type="email" name="sender" required="" id="id_sender">
#     <label for="id_cc_myself">Cc myself:</label><input type="checkbox" name="cc_myself" id="id_cc_myself">
#     <input type="submit" value="Submit">
# </form>


# 通过直接form.as_p生成的HTML文件如下
# <form action="/name/" method="post">
#     {% csrf_token %}
#     {{ form.as_p }}
#     <input type="submit" value="Submit" />
# </form>

# 渲染后:
# <form action="/name/" method="post">
#     <input type="hidden" name="csrfmiddlewaretoken" value="bT7RLCRW7B40rLZye7rtQ9n2Nr0tvcfVIGNrwC4xq6TmdtW40yJr1jMiNyFrtxRY">
#     <p><label for="id_subject">Subject:</label> <input type="text" name="subject" maxlength="100" required="" id="id_subject"></p>
#     <p><label for="id_message">Message:</label> <textarea name="message" cols="40" rows="10" required="" id="id_message"></textarea></p>
#     <p><label for="id_sender">Sender:</label> <input type="email" name="sender" required="" id="id_sender"></p>
#     <p><label for="id_cc_myself">Cc myself:</label> <input type="checkbox" name="cc_myself" id="id_cc_myself"></p>
#     <input type="submit" value="Submit">
# </form>


# 直接{{ form }}虽然好，啥都不用操心，但是往往并不是你想要的，比如你要使用CSS和JS，比如你要引入Bootstarps框架，这些都需要对表单内的input元素进行额外控制，那怎么办呢？手动渲染字段就可以了。
# 可以通过{{ form.name_of_field }}获取每一个字段，然后分别渲染，如下例所示：

# {{ form.non_field_errors }}
# <div class="fieldWrapper">
#     {{ form.subject.errors }}
#     <label for="{{ form.subject.id_for_label }}">Email subject:</label>
#     {{ form.subject }}
# </div>
# <div class="fieldWrapper">
#     {{ form.message.errors }}
#     <label for="{{ form.message.id_for_label }}">Your message:</label>
#     {{ form.message }}
# </div>
# <div class="fieldWrapper">
#     {{ form.sender.errors }}
#     <label for="{{ form.sender.id_for_label }}">Your email address:</label>
#     {{ form.sender }}
# </div>
# <div class="fieldWrapper">
#     {{ form.cc_myself.errors }}
#     <label for="{{ form.cc_myself.id_for_label }}">CC yourself?</label>
#     {{ form.cc_myself }}
# </div>


# 渲染后:
# < div class ="fieldWrapper" >
#     < label for ="id_subject" > Email subject:</label>
#     < input type = "text" name = "subject" maxlength = "100" required = "" id = "id_subject" >
# </div >
#
# < div class ="fieldWrapper" >
#     < labelfor ="id_message" > Your message:< / label >
#     < textarea name = "message" cols = "40" rows = "10" required = "" id = "id_message" > < / textarea >
# </div>
#
# < div class ="fieldWrapper" >
#     < label for ="id_sender" > Your email address:< / label >
#     < input type = "email" name = "sender" required = "" id = "id_sender" >
# </div >
#
# <div class ="fieldWrapper" >
#     <label for ="id_cc_myself" > CC yourself? < / label >
#     <input type = "checkbox" name = "cc_myself" id = "id_cc_myself" >
# </div>


# 4. 循环表单的字段：
# 如果你的表单字段有相同格式的HMTL表现，那么完全可以循环生成，不必要手动的编写每个字段，减少冗余和重复代码，只需要使用模板语言中的{% for %}循环，如下所示：
# {% for field in form %}
#     <div class="fieldWrapper">
#         {{ field.errors }}
#         {{ field.label_tag }} {{ field }}
#         {% if field.help_text %}
#         <p class="help">{{ field.help_text|safe }}</p>
#         {% endif %}
#     </div>
# {% endfor %}
View Code

{{ field }}中非常有用的属性，这些都是Django内置的模板语言给我们提供的方便：

属性    说明
{{ field.label }}    字段对应的label信息
{{ field.label_tag }}    自动生成字段的label标签，注意与{{ field.label }}的区别。
{{ field.id_for_label }}    自定义字段标签的id
{{ field.value }}    当前字段的值，比如一个Email字段的值someone@example.com
{{ field.html_name }}    指定字段生成的input标签中name属性的值
{{ field.help_text }}    字段的帮助信息
{{ field.errors }}    包含错误信息的元素
{{ field.is_hidden }}    用于判断当前字段是否为隐藏的字段，如果是，返回True
{{ field.field }}    返回字段的参数列表。例如{{ char_field.field.max_length }}
View Code

详细可参考:https://www.cnblogs.com/yangmingxianshen/p/8396535.html 或

刘江博客:http://www.liujiangblog.com/course/django/153

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原文地址：https://www.cnblogs.com/Mixtea/p/10447404.html