Django学习--form(表单)

01 表单基础

1.1概念

在html中，一个表单的元素是<form>.....</form>，在表单里面允许visitor做输入文本，选择，提交对象等等工作。对于当中<input>元素，明白用户输入的数据应该被返回的，还有这个数据应该通过哪种HTTP方式返回数据

1.2http method

对于表单数据的传输，主要两种方式：post和get，其中get方式数据从url传递，比如https://docs.djangoproject.com/search/?q=forms&release=1，其中数据为q='fomrs',release=1. 另一种方式是post方式，其数据在

1.3.过程

比如用户登录过程，用户在界面上输入用户名和密码，经过post方式提交后其数据就会被传入到对应的视图函数，并且将其经过某种处理进行验证

02 表单建立

2.1获取用户名

<form action="/username/" method="post">
    <label for="user_name">User name: </label>
    <input id="user_name" type="text" name="user_name" value="{{ current_name }}">
    <input type="submit" value="OK">
</form>

2.2使用Django建立表单

在应用目录下新建forms.py

from django import forms

class NameForm(forms.Form):
    your_name = forms.CharField(label='Your name', max_length=100)

2.3视图函数对数据验证，views.py

From 类有一个方法is_valid()，来验证是否满足要求

from django.http import HttpResponseRedirect
from django.shortcuts import render

from .forms import NameForm

def get_name(request):
    # if this is a POST request we need to process the form data
    if request.method == 'POST':
        # create a form instance and populate it with data from the request:
        form = NameForm(request.POST)
        # check whether it's valid:
        if form.is_valid():
            # process the data in form.cleaned_data as required
            # ...
            # redirect to a new URL:
            return HttpResponseRedirect('/thanks/')

    # if a GET (or any other method) we'll create a blank form
    else:
        form = NameForm()

    return render(request, 'name.html', {'form': form})

03 模型创建表单

3.1Django提供一个帮助类(ModelForm)可以从一个django模型创建一个Form类

3.2创建Article

>>> from django.forms import ModelForm
>>> from myapp.models import Article

# Create the form class.
>>> class ArticleForm(ModelForm):
...     class Meta:
...         model = Article
...         fields = ['pub_date', 'headline', 'content', 'reporter']

# Creating a form to add an article.
>>> form = ArticleForm()

# Creating a form to change an existing article.
>>> article = Article.objects.get(pk=1)
>>> form = ArticleForm(instance=article)

3.3一个完整的例子

from django.db import models
from django.forms import ModelForm

TITLE_CHOICES = (
    ('MR', 'Mr.'),
    ('MRS', 'Mrs.'),
    ('MS', 'Ms.'),
)

class Author(models.Model):
    name = models.CharField(max_length=100)
    title = models.CharField(max_length=3, choices=TITLE_CHOICES)
    birth_date = models.DateField(blank=True, null=True)

    def __str__(self):
        return self.name

class Book(models.Model):
    name = models.CharField(max_length=100)
    authors = models.ManyToManyField(Author)

class AuthorForm(ModelForm):
    class Meta:
        model = Author
        fields = ['name', 'title', 'birth_date']

class BookForm(ModelForm):
    class Meta:
        model = Book
        fields = ['name', 'authors']