• Django Form 组件


    文章对应的B站视频:https://www.bilibili.com/video/BV1Tu41127Ca/

    Django系列文章对应的目录:https://www.cnblogs.com/emanlee/p/15860241.html

    Django Form 组件

    Django Form 组件用于对页面进行初始化,生成 HTML 标签,此外还可以对用户提交对数据进行校验(显示错误信息)。

    报错信息显示顺序:

    • 先显示字段属性中的错误信息,然后再显示局部钩子的错误信息。
    • 若显示了字段属性的错误信息,就不会显示局部钩子的错误信息。
    • 若有全局钩子,则全局钩子是等所有的数据都校验完,才开始进行校验,并且全局钩子的错误信息一定会显示。

    使用 Form 组件,需要先导入 forms:

    from django import forms

    接下来我们在 app01 目录下创建一个 My_forms.py:

    app01/My_forms.py

    from django import forms
    from django.core.exceptions import ValidationError
    from app01 import models
    
    class EmpForm(forms.Form):
        name = forms.CharField(min_length=4, label="姓名", error_messages={"min_length": "太短了", "required": "该字段不能为空!"})
        age = forms.IntegerField(label="年龄")
        salary = forms.DecimalField(label="工资")

    字段属性:

    • label:输入框前面的文本信息。
    • error_message:自定义显示的错误信息,属性值是字典, 其中 required 为设置不能为空时显示的错误信息的 key。

    app01/views.py

    from django.shortcuts import render, HttpResponse
    from app01.My_forms import EmpForm
    from app01 import models
    from django.core.exceptions import ValidationError
    # Create your views here.
    
    
    def add_emp(request):
        if request.method == "GET":
            form = EmpForm()
            return render(request, "add_emp.html", {"form": form})
        else:
            form = EmpForm(request.POST)
            if form.is_valid():  # 进行数据校验
                # 校验成功
                data = form.cleaned_data  # 校验成功的值,会放在cleaned_data里。
                data.pop('r_salary')
                print(data)
    
                models.Emp.objects.create(**data)
                return HttpResponse(
                    'ok'
                )
                # return render(request, "add_emp.html", {"form": form})
            else:
                print(form.errors)    # 打印错误信息
                clean_errors = form.errors.get("__all__")
                print(222, clean_errors)
            return render(request, "add_emp.html", {"form": form, "clean_errors": clean_errors})

    app01/urls.py 文件添加以下规则:

    from django.urls import path
    from . import views
    
    urlpatterns = [
        path('add_emp/', views.add_emp)
    ]

    settings.py 配置:

    TEMPLATES 里面的 DIRS
    import os
    TEMPLATES = [
        {
            'BACKEND': 'django.template.backends.django.DjangoTemplates',
            'DIRS': [os.path.join(BASE_DIR, 'app01')],
            'APP_DIRS': True,
            'OPTIONS': {
                'context_processors': [
                    'django.template.context_processors.debug',
                    'django.template.context_processors.request',
                    'django.contrib.auth.context_processors.auth',
                    'django.contrib.messages.context_processors.messages',
                ],
            },
        },
    ]

     MIDDLEWARE,把下面的'django.middleware.csrf.CsrfViewMiddleware',注释掉

    MIDDLEWARE = [
        'django.middleware.security.SecurityMiddleware',
        'django.contrib.sessions.middleware.SessionMiddleware',
        'django.middleware.common.CommonMiddleware',
        #'django.middleware.csrf.CsrfViewMiddleware',
        'django.contrib.auth.middleware.AuthenticationMiddleware',
        'django.contrib.messages.middleware.MessageMiddleware',
        'django.middleware.clickjacking.XFrameOptionsMiddleware',
    ]

    HTML 模版:

    app01/add_emp.html

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
     
    <h3>添加员工</h3>
     
    {#1、自己手动写HTML页面#}
    <form action="" method="post">
        <p>姓名:<input type="text" name="name"></p>
        <p>年龄:<input type="text" name="age"></p>
        <p>工资:<input type="text" name="salary"></p>
        <input type="submit">
    </form>
     
    {#2、通过form对象的as_p方法实现#}
    {#<form action="" method="post" novalidate>#}
    {#    {% csrf_token %}#}
    {#    {{ form.as_p }}#}
    {#    <input type="submit">#}
    {#</form>#}
     
    {#3、手动获取form对象的字段#}
    {#<form action="" method="post" novalidate>#}
    {#    {% csrf_token %}#}
    {#    <div>#}
    {#        <label for="id_{{ form.name.name }}">姓名</label>#}
    {#        {{ form.name }} <span>{{ form.name.errors.0 }}</span>#}
    {#    </div>#}
    {#    <div>#}
    {#        <label for="id_{{ form.age.name }}">年龄</label>#}
    {#        {{ form.age }} <span>{{ form.age.errors.0 }}</span>#}
    {#    </div>#}
    {#    <div>#}
    {#        <label for="id_salary">工资</label>#}
    {#        {{ form.salary }} <span>{{ form.salary.errors.0 }}</span>#}
    {#    </div>#}
    {#    <input type="submit">#}
    {#</form>#}
     
     
    {#4、用for循环展示所有字段#}
    {#<form action="" method="post" novalidate>#}
    {#    {% csrf_token %}#}
    {#    {% for field in form %}#}
    {#        <div>#}
    {#            <label for="id_{{ field.name }}">{{ field.label }}</label>#}
    {#            {{ field }} <span>{{ field.errors.0 }}</span>#}
    {#        </div>#}
    {#    {% endfor %}#}
    {#    <input type="submit">#}
    {#</form>#}
     
    </body>
    </html>

    http://127.0.0.1:8003/add_emp/


    运行结果如下图所示:

    把 app01/add_emp.html 的 #1 注释掉, #2 去掉注释,然后测试.

      

    局部钩子和全局钩子

    定义 Form 类:

    app01/My_forms.py

    from django import forms
    from django.core.exceptions import ValidationError
    from app01 import models
    class EmpForm(forms.Form):
        name = forms.CharField(min_length=5, label="姓名", error_messages={"required": "该字段不能为空!",
                                                                         "min_length": "用户名太短。"})
        age = forms.IntegerField(label="年龄")
        salary = forms.DecimalField(max_digits=5, decimal_places=2, label="工资")
        r_salary = forms.DecimalField(max_digits=5, decimal_places=2, label="请再输入工资")
    
    
        def clean_name(self):  # 局部钩子
            val = self.cleaned_data.get("name")
    
    
            if val.isdigit():
                raise ValidationError("用户名不能是纯数字")
            elif models.Emp.objects.filter(name=val):
                raise ValidationError("用户名已存在!")
            else:
                return val
    
        def clean(self):  # 全局钩子 确认两次输入的工资是否一致。
            val = self.cleaned_data.get("salary")
            r_val = self.cleaned_data.get("r_salary")
    
    
            if val == r_val:
                return self.cleaned_data
            else:
                raise ValidationError("请确认工资是否一致。")

    views.py 文件代码:

    app01/views.py

    def add_emp(request):
        if request.method == "GET":
            form = EmpForm()  # 初始化form对象
            return render(request, "add_emp.html", {"form":form})
        else:
            form = EmpForm(request.POST)  # 将数据传给form对象
            if form.is_valid():  # 进行校验
                data = form.cleaned_data
                data.pop("r_salary")
                models.Emp.objects.create(**data)
                return redirect("/index/")
            else:  # 校验失败
                clear_errors = form.errors.get("__all__")  # 获取全局钩子错误信息
                return render(request, "add_emp.html", {"form": form, "clear_errors": clear_errors})

    模板文件代码如下:

    app01/add_emp.html

    <form action="" method="post" novalidate>
        {% csrf_token %}
        <div>
            <label for="id_{{ form.name.name }}">姓名</label>
            {{ form.name }} <span>{{ form.name.errors.0 }}</span>
        </div>
        <div>
            <label for="id_{{ form.age.name }}">年龄</label>
            {{ form.age }} <span>{{ form.age.errors.0 }}</span>
        </div>
        <div>
            <label for="id_salary">工资</label>
            {{ form.salary }} <span>{{ form.salary.errors.0 }}{{ clear_errors.0 }}</span>
        </div>
        <div>
            <label for="id_r_salary">请再输入工资</label>
            {{ form.r_salary }} <span>{{ form.r_salary.errors.0 }}{{ clear_errors.0 }}</span>
        </div>
        <input type="submit">
    </form>

    运行结果如下图所示:

    https://www.runoob.com/django/django-form-component.html

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  • 原文地址:https://www.cnblogs.com/emanlee/p/15856370.html
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