Django中form和modelform学习

1 初识Form

当我们需要对注册界面或者登陆界面等，需要我们填写信息的网页进行校验时，即填写内容不能为空，如果按之前的方式我们需要写好多if..else语句来实现字段校验，这是不方便的，由此我们可以引出form和modelform

1. views.py

class MyForm(Form):
    user = forms.CharField(widget=forms.Input)
    pwd = form.CharFiled(widget=forms.Input)
    email = form.CharFiled(widget=forms.Input)
    account = form.CharFiled(widget=forms.Input)
    create_time = form.CharFiled(widget=forms.Input)
    depart = form.CharFiled(widget=forms.Input)
    gender = form.CharFiled(widget=forms.Input)


def user_add(request):
    if request.method == "GET":
        form = MyForm()
        return render(request, 'user_add.html',{"form":form})

2.user_add.html

<form method="post">
    {% for field in form%}
    	{{ field }}
    {% endfor %}
    <!-- <input type="text"  placeholder="姓名" name="user" /> -->
</form>

<form method="post">
    {{ form.user }}
    {{ form.pwd }}
    {{ form.email }}
    <!-- <input type="text"  placeholder="姓名" name="user" /> -->
</form>

如上将可以在html页面自动生成输入框，而如果引入很多字段需要在myform里需要写很多

由此引出modelform

3 ModelForm（推荐）

0. models.py

class UserInfo(models.Model):
    """ 员工表 """
    name = models.CharField(verbose_name="姓名", max_length=16)
    password = models.CharField(verbose_name="密码", max_length=64)
    age = models.IntegerField(verbose_name="年龄")
    account = models.DecimalField(verbose_name="账户余额", max_digits=10, decimal_places=2, default=0)
    create_time = models.DateTimeField(verbose_name="入职时间")
    depart = models.ForeignKey(to="Department", to_field="id", on_delete=models.CASCADE)
    gender_choices = (
        (1, "男"),
        (2, "女"),
    )
    gender = models.SmallIntegerField(verbose_name="性别", choices=gender_choices)

1. views.py

class MyForm(ModelForm):
    xx = form.CharField*("...")#新加不在数据库中的字段
    class Meta:
        model = UserInfo
        fields = ["name","password","age","xx"]#选择需要的字段即可


def user_add(request):
    if request.method == "GET":
        form = MyForm()
        return render(request, 'user_add.html',{"form":form})

2.user_add.html

<form method="post">
    {% for field in form%}
    	{{ field }}
    {% endfor %}
    <!-- <input type="text"  placeholder="姓名" name="user" /> -->
</form>

<form method="post">
    {{ form.user }}
    {{ form.pwd }}
    {{ form.email }}
    <!-- <input type="text"  placeholder="姓名" name="user" /> -->
</form>

引入外键表时：

写上部分depart时，返回的是一个个对象，没有读到里面的title，这时候需要用面向对象知识里学到的

#__str__()函数
class Department(models.Model):
    """ 部门表 """
    title = models.CharField(verbose_name='标题', max_length=32)

    def __str__(self):
        return self.title
#这样返回的才是部门名称

field.label

指的是数据库中的verbose_name，modelform会自动帮我们读取verbose_name，如果没有该参数将读取字段名

需要为自动生成的输入框添加样式

class MyForm(ModelForm):
    xx = form.CharField*("...")#新加不在数据库中的字段
    class Meta:
        model = UserInfo
        fields = ["name","password","age","xx"]#选择需要的字段即可
    def __init__(self,*args,**kwargs):
        super().__init__(*args,**kwargs)
        for name,field in self.fields.items():
            #if name == "password":让某些字段加或者不加
            field.widget.attrs={"class":"xx样式","placeholder"：field.label}

校验过程

def user_model_form_add(request):
    """ 添加用户（ModelForm版本）"""
    if request.method == "GET":
        form = UserModelForm()
        return render(request, 'user_model_form_add.html', {"form": form})

    # 用户POST提交数据，数据校验。
    form = UserModelForm(data=request.POST)
    if form.is_valid():
        # 如果数据合法，保存到数据库
        # {'name': '123', 'password': '123', 'age': 11, 'account': Decimal('0'), 'create_time': datetime.datetime(2011, 11, 11, 0, 0, tzinfo=<UTC>), 'gender': 1, 'depart': <Department: IT运维部门>}
        # print(form.cleaned_data)
        # models.UserInfo.objects.create(..)
        form.save()#直接用这个即可
        return redirect('/user/list/')

    # 校验失败（在页面上显示错误信息）
    return render(request, 'user_model_form_add.html', {"form": form})

html界面：

{% extends 'layout.html' %}


{% block content %}

    <div class="container">
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title"> 新建用户 </h3>
            </div>
            <div class="panel-body">
                <form method="post" novalidate>
                    {% csrf_token %}

                    {% for field in form %}
                        <div class="form-group">
                            <label>{{ field.label }}</label>
                            {{ field }}
                            <span style="color: red;">{{ field.errors.0 }}</span>
                        </div>
                    {% endfor %}

                    <button type="submit" class="btn btn-primary">提 交</button>
                </form>
            </div>
        </div>
    </div>

{% endblock %}

模板html页面就不放了，读取错误时只读errors.0即可

如果有其他需要做验证的规则，可以在views中

class UserModelForm(forms.ModelForm):
    name = forms.CharField(min_length=3, label="用户名")

    class Meta:
        model = models.UserInfo
        fields = ["name", "password", "age", 'account', 'create_time', "gender", "depart"]
        # widgets = {
        #     "name": forms.TextInput(attrs={"class": "form-control"}),
        #     "password": forms.PasswordInput(attrs={"class": "form-control"}),
        #     "age": forms.TextInput(attrs={"class": "form-control"}),
        # }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # 循环找到所有的插件，添加了class="form-control"
        for name, field in self.fields.items():
            # if name == "password":
            #     continue
            field.widget.attrs = {"class": "form-control", "placeholder": field.label}

如上的name中写min_length=3这样去做验证

报错为英文，想要修改为中文

settings中

设置

# LANGUAGE_CODE = 'en-us'
LANGUAGE_CODE = 'zh-hans'

如上

编辑修改功能

主要是要考虑修改当前而非新增用户

def user_edit(request, nid):
    """ 编辑用户 """
    row_object = models.UserInfo.objects.filter(id=nid).first()

    if request.method == "GET":
        # 根据ID去数据库获取要编辑的那一行数据（对象）
        form = UserModelForm(instance=row_object)
        return render(request, 'user_edit.html', {'form': form})

    form = UserModelForm(data=request.POST, instance=row_object)
    if form.is_valid():
        # 默认保存的是用户输入的所有数据，如果想要再用户输入以外增加一点值，即将某些字段设为固定值
        # form.instance.字段名 = 值
        form.save()
        return redirect('/user/list/')
    return render(request, 'user_edit.html', {"form": form})