Django框架 之 form组件
Django框架 之 form组件
浏览目录
-
Form介绍
- 普通的登录
- 使用form组件
-
Form详情
-
常用字段
-
校验
-
进阶
-
- 使用Django Form流程
一、Form介绍
我们之前在HTML页面中利用form表单向后端提交数据时,都会写一些获取用户输入的标签并且用form标签把它们包起来。
与此同时我们在好多场景下都需要对用户的输入做校验,比如校验用户是否输入,输入的长度和格式等正不正确。如果用户输入的内容有错误就需要在页面上相应的位置显示显示对应的错误信息.。
Django form组件就实现了上面所述的功能。
总结一下,其实form组件的主要功能如下:
- 生成页面可用的HTML标签
- 对用户提交的数据进行校验
- 保留上次输入内容
- 自动生成错误信息
- 自动创建input标签并设置样式
1、普通的登录
views.py
1
2
3
4
5
6
7
8
9
10
|
def login(request): error_msg = "" if request.method = = "POST" : username = request.POST.get( "username" ) pwd = request.POST.get( "pwd" ) if username = = yaya " and pwd == " 123456 ": return HttpResponse( "OK" ) else : error_msg = "用户名或密码错误" return render(request, "login.html" , { "error_msg" : error_msg}) |
login.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
<! DOCTYPE html> < html lang="en"> < head > < meta charset="UTF-8"> < meta http-equiv="x-ua-compatible" content="IE=edge"> < meta name="viewport" content="width=device-width, initial-scale=1"> < title >login</ title > < style > .error { color: red; } </ style > </ head > < body > < form action="/login/" method="post"> {% csrf_token %} < p > < label for="username">用户名</ label > < input type="text" name="username" id="username"> </ p > < p > < label for="pwd">密码</ label > < input type="password" name="pwd" id="pwd"> < span class="error"></ span > </ p > < p > < input type="submit"> < span class="error">{{ error_msg }}</ span > </ p > </ form > </ body > </ html > |
2、使用form组件
先定义好一个LoginForm类。
views.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
class LoginForm(forms.Form): username = forms.CharField(min_length = 8 , label = "用户名" ) pwd = forms.CharField(min_length = 6 , label = "密码" ) def login2(request): error_msg = "" form_obj = LoginForm() if request.method = = "POST" : form_obj = LoginForm(request.POST) if form_obj.is_valid(): username = form_obj.cleaned_data.get( "username" ) pwd = form_obj.cleaned_data.get( "pwd" ) if username = = "yaya" and pwd = = "123456" : return HttpResponse( "OK" ) else : error_msg = "用户名或密码错误" return render(request, "login2.html" , { "form_obj" : form_obj, "error_msg" : error_msg}) |
login.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
<! DOCTYPE html> < html lang="en"> < head > < meta charset="UTF-8"> < meta http-equiv="x-ua-compatible" content="IE=edge"> < meta name="viewport" content="width=device-width, initial-scale=1"> < title >login</ title > < style > .error { color: red; } </ style > </ head > < body > < form action="/login/" method="post" novalidate> {% csrf_token %} < p > {{ form_obj.username.label }} {{ form_obj.username }} < span class="error">{{ form_obj.username.errors.0 }}</ span > </ p > < p > {{ form_obj.pwd.label }} {{ form_obj.pwd }} < span class="error">{{ form_obj.pwd.errors.0 }}</ span > </ p > < p > < input type="submit"> < span class="error">{{ error_msg }}</ span > </ p > </ form > </ body > </ html > |
看网页效果发现 也验证了form的功能:
• 前端页面是form类的对象生成的 -->生成HTML标签功能
• 当用户名和密码输入为空或输错之后 页面都会提示 -->用户提交校验功能
• 当用户输错之后 再次输入 上次的内容还保留在input框 -->保留上次输入内容
二、Form详情
1、常用字段
initial
初始值,input框里面的初始值。
1
2
3
4
5
6
7
|
class LoginForm(forms.Form): username = forms.CharField( min_length = 8 , label = "用户名" , initial = "张三" # 设置默认值 ) pwd = forms.CharField(min_length = 6 , label = "密码" ) |
error_messages
重写错误信息。
1
2
3
4
5
6
7
8
9
10
11
12
|
class LoginForm(forms.Form): username = forms.CharField( min_length = 8 , label = "用户名" , initial = "张三" , error_messages = { "required" : "不能为空" , "invalid" : "格式错误" , "min_length" : "用户名最短8位" } ) pwd = forms.CharField(min_length = 6 , label = "密码" ) |
password
input框的type转换为password类型。
1
2
3
4
5
6
7
|
class LoginForm(forms.Form): ... pwd = forms.CharField( min_length = 6 , label = "密码" , widget = forms.widgets.PasswordInput(attrs = { 'class' : 'c1' }, render_value = True ) ) |
radioSelect
单radio值为字符串。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
class LoginForm(forms.Form): username = forms.CharField( min_length = 8 , label = "用户名" , initial = "张三" , error_messages = { "required" : "不能为空" , "invalid" : "格式错误" , "min_length" : "用户名最短8位" } ) pwd = forms.CharField(min_length = 6 , label = "密码" ) gender = forms.fields.ChoiceField( choices = (( 1 , "男" ), ( 2 , "女" ), ( 3 , "保密" )), label = "性别" , initial = 3 , widget = forms.widgets.RadioSelect ) |
单选Select
单选的选择框
1
2
3
4
5
6
7
8
|
class LoginForm(forms.Form): ... hobby = forms.fields.ChoiceField( choices = (( 1 , "篮球" ), ( 2 , "足球" ), ( 3 , "双色球" ), ), label = "爱好" , initial = 3 , widget = forms.widgets.Select ) |
多选Select
多选的选择框
1
2
3
4
5
6
7
8
|
class LoginForm(forms.Form): ... hobby = forms.fields.MultipleChoiceField( choices = (( 1 , "篮球" ), ( 2 , "足球" ), ( 3 , "双色球" ), ), label = "爱好" , initial = [ 1 , 3 ], widget = forms.widgets.SelectMultiple ) |
单选checkbox
单选下拉框
1
2
3
4
5
6
7
|
class LoginForm(forms.Form): ... keep = forms.fields.ChoiceField( label = "是否记住密码" , initial = "checked" , widget = forms.widgets.CheckboxInput ) |
多选checkbox
多选下拉框
1
2
3
4
5
6
7
8
|
class LoginForm(forms.Form): ... hobby = forms.fields.MultipleChoiceField( choices = (( 1 , "篮球" ), ( 2 , "足球" ), ( 3 , "双色球" ),), label = "爱好" , initial = [ 1 , 3 ], widget = forms.widgets.CheckboxSelectMultiple ) |
关于choice的注意事项:
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:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
from django.forms import Form from django.forms import widgets from django.forms import fields 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 ().values_list( 'id' , 'caption' ) |
方式二:
1
2
3
4
5
6
7
8
|
from django import forms from django.forms import fields from django.forms import models as form_model class FInfo(forms.Form): authors = form_model.ModelMultipleChoiceField(queryset = models.NNewType.objects. all ()) # authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all()) |
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
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=None, 最大值 min_value=None, 最小值 FloatField(IntegerField) ... DecimalField(IntegerField) max_value=None, 最大值 min_value=None, 最小值 max_digits=None, 总长度 decimal_places=None, 小数位长度 BaseTemporalField(Field) input_formats=None 时间格式化 DateField(BaseTemporalField) 格式:2015-09-01 TimeField(BaseTemporalField) 格式:11:12 DateTimeField(BaseTemporalField)格式:2015-09-01 11:12 DurationField(Field) 时间间隔:%d %H:%M:%S.%f ... RegexField(CharField) regex, 自定制正则表达式 max_length=None, 最大长度 min_length=None, 最小长度 error_message=None, 忽略,错误信息使用 error_messages={'invalid': '...'} EmailField(CharField) ... FileField(Field) allow_empty_file=False 是否允许空文件 ImageField(FileField) ... 注:需要PIL模块,pip3 install Pillow 以上两个字典使用时,需要注意两点: - form表单中 enctype="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= '' 空值的默认值 MultipleChoiceField(ChoiceField) ... TypedMultipleChoiceField(MultipleChoiceField) coerce = lambda val: val 对选中的每一个值进行一次转换 empty_value= '' 空值的默认值 ComboField(Field) fields=() 使用多个验证,如下:即验证最大长度20,又验证邮箱格式 fields.ComboField(fields=[fields.CharField(max_length=20), fields.EmailField(),]) MultiValueField(Field) PS: 抽象类,子类中可以实现聚合多个字典去匹配一个值,要配合MultiWidget使用 SplitDateTimeField(MultiValueField) input_date_formats=None, 格式列表:['%Y--%m--%d', '%m%d/%Y', '%m/%d/%y'] input_time_formats=None 格式列表:['%H:%M:%S', '%H:%M:%S.%f', '%H:%M'] FilePathField(ChoiceField) 文件选项,目录下文件显示在页面中 path, 文件夹路径 match=None, 正则匹配 recursive=False, 递归下面的文件夹 allow_files=True, 允许文件 allow_folders=False, 允许文件夹 required=True, widget=None, label=None, initial=None, help_text='' GenericIPAddressField protocol='both', both,ipv4,ipv6支持的IP格式 unpack_ipv4=False 解析ipv4地址,如果是::ffff:192.0.2.1时候,可解析为192.0.2.1, PS:protocol必须为both才能启用 SlugField(CharField) 数字,字母,下划线,减号(连字符) ... UUIDField(CharField) uuid类型
2、校验
方式一
1
2
3
4
5
6
7
8
9
|
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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
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' })) |
3、进阶
应用Bootstrap样式
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="x-ua-compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css"> <title>login</title> </head> <body> <div class="container"> <div class="row"> <form action="/login2/" method="post" novalidate class="form-horizontal"> {% csrf_token %} <div class="form-group"> <label for="{{ form_obj.username.id_for_label }}" class="col-md-2 control-label">{{ form_obj.username.label }}</label> <div class="col-md-10"> {{ form_obj.username }} <span class="help-block">{{ form_obj.username.errors.0 }}</span> </div> </div> <div class="form-group"> <label for="{{ form_obj.pwd.id_for_label }}" class="col-md-2 control-label">{{ form_obj.pwd.label }}</label> <div class="col-md-10"> {{ form_obj.pwd }} <span class="help-block">{{ form_obj.pwd.errors.0 }}</span> </div> </div> <div class="form-group"> <label class="col-md-2 control-label">{{ form_obj.gender.label }}</label> <div class="col-md-10"> <div class="radio"> {% for radio in form_obj.gender %} <label for="{{ radio.id_for_label }}"> {{ radio.tag }}{{ radio.choice_label }} </label> {% endfor %} </div> </div> </div> <div class="form-group"> <div class="col-md-offset-2 col-md-10"> <button type="submit" class="btn btn-default">注册</button> </div> </div> </form> </div> </div> <script src="/static/jquery-3.2.1.min.js"></script> <script src="/static/bootstrap/js/bootstrap.min.js"></script> </body> </html>
批量添加样式
可通过重写form类的init方法来实现。
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
class LoginForm(forms.Form): username = forms.CharField( min_length=8, label="用户名", initial="张三", error_messages={ "required": "不能为空", "invalid": "格式错误", "min_length": "用户名最短8位" } ... def __init__(self, *args, **kwargs): super(LoginForm, self).__init__(*args, **kwargs) for field in iter(self.fields): self.fields[field].widget.attrs.update({ 'class': 'form-control' })
三、使用Django Form流程
1、urls.py配置关系映射
2、views.py中创建Form类,定义字段的校验条件,在映射关系中实例化Form类,进行逻辑处理,将Form对象通过响应Response返回页面中
3、页面中调用实例化Form对象进行操作
form对象渲染样式:
方式一
1
2
3
|
{{ form.as_table }} 以表格的形式将它们渲染在<tr> 标签中 {{ form.as_p }} 将它们渲染在<p> 标签中 {{ form.as_ul }} 将它们渲染在<li> 标签中 |
整体导入,应用不方便没有特殊样式。
方式二
1
|
{{form.user}} |
优点:使用方便,随意修改特殊样式;
缺点:如果标签太多,操作会很麻烦。
方式三
1
2
3
4
5
6
7
8
|
{ % for field in form % } <div> <label for = "">{{ field.label }}< / label> <div> {{ field }} < / div> < / div> { % endfor % } |
for循环,代码简捷,操作方便,效率高,但不便添加特殊样式。
示例:注册
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
from app01 import views urlpatterns = [ url(r'^admin/', admin.site.urls), url(r'^register/', views.register), ]
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
#models里面建表 class UserInfo(models.Model): user = models.CharField(max_length=32) pwd = models.CharField(max_length=32) def __str__(self): return self.user
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
#在项目里新建forms.py from django import forms class RegisterForm(forms.Form): user = forms.CharField( min_length=6, label="用户名", error_messages={ "required": "用户名不能为空", "min_length": "用户名不能小于6位", } ) pwd = forms.CharField( label="密码", min_length=6, error_messages={ "required": "密码不能为空", "min_length": "密码不能小于6位", }, widget=forms.widgets.PasswordInput() )
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
from django.shortcuts import render, HttpResponse from app01 import forms, models # Create your views here. def register(request): # 实例化一个form示例 form_obj = forms.RegisterForm() if request.method == "POST": # 把POST提交过来的数据传到form表单里 form_obj = forms.RegisterForm(request.POST) # 调用实例化对象的is_valid()方法,帮我做校验! if form_obj.is_valid(): # 校验通过 # form_obj.cleaned_data <-- 所有有效的数据都存放在cleaned_data属性中 # user = form_obj.cleaned_data.get("user") # pwd = form_obj.cleaned_data.get("pwd") # 调用ORM,在数据库中创建新的用户 # models.UserInfo.objects.create(user=user, pwd=pwd) # print(form_obj.cleaned_data) models.UserInfo.objects.create(**form_obj.cleaned_data) return HttpResponse("O98K") # else: # # 校验失败 # # 此时,form_obj.errors 里面保存了报错的信息 # return render(request, "register.html", {"form_obj": form_obj}) return render(request, "register.html", {"form_obj": form_obj})
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
<!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <h1>欢迎注册!</h1> <form action="" method="post" novalidate> {% csrf_token %} <p> <label for="{{ form_obj.user.id_for_label }}">{{ form_obj.user.label }}</label> {{ form_obj.user }} <span>{{ form_obj.user.errors.0 }}</span> </p> <p> <label for="{{ form_obj.pwd.id_for_label }}">{{ form_obj.pwd.label }}</label> {{ form_obj.pwd }} <span>{{ form_obj.pwd.errors.0 }}</span> </p> <p> <input type="submit" value="注册"> </p> </form> </body> </html>