Django杂货铺－Class based views

 

本节内容

Class basesd views介绍

Class basesd views使用

 

 

Class basesd views介绍

In the beginning there was only the view function contract, Django passed your function an HttpRequest and expected back anHttpResponse. This was the extent of what Django provided.

Early on it was recognized that there were common idioms and patterns found in view development. Function-based generic views were introduced to abstract these patterns and ease view development for the common cases.

The problem with function-based generic views is that while they covered the simple cases well, there was no way to extend or customize them beyond some simple configuration options, limiting their usefulness in many real-world applications.

Class-based generic views were created with the same objective as function-based generic views, to make view development easier. However, the way the solution is implemented, through the use of mixins, provides a toolkit that results in class-based generic views being more extensible and flexible than their function-based counterparts.

If you have tried function based generic views in the past and found them lacking, you should not think of class-based generic views as simply a class-based equivalent, but rather as a fresh approach to solving the original problems that generic views were meant to solve.

 

基本的Class based view

下面代码用function view写如下

from django.http import HttpResponse

def my_view(request):
    if request.method == 'GET':
        # <view logic>
        return HttpResponse('result')

 

如果用class based view写

from django.http import HttpResponse
from django.views import View

class MyView(View):
    def get(self, request):
        # <view logic>
        return HttpResponse('result')

　　

url里配置如下

# urls.py
from django.conf.urls import url
from myapp.views import MyView

urlpatterns = [
    url(r'^about/$', MyView.as_view()),
]

 

Class based views 中处理forms

 用function base写

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

from .forms import MyForm

def myview(request):
    if request.method == "POST":
        form = MyForm(request.POST)
        if form.is_valid():
            # <process form cleaned data>
            return HttpResponseRedirect('/success/')
    else:
        form = MyForm(initial={'key': 'value'})

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

用class base view写

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

from .forms import MyForm

class MyFormView(View):
    form_class = MyForm
    initial = {'key': 'value'}
    template_name = 'form_template.html'

    def get(self, request, *args, **kwargs):
        form = self.form_class(initial=self.initial)
        return render(request, self.template_name, {'form': form})

    def post(self, request, *args, **kwargs):
        form = self.form_class(request.POST)
        if form.is_valid():
            # <process form cleaned data>
            return HttpResponseRedirect('/success/')

        return render(request, self.template_name, {'form': form})