一、项目创建成功后，首先写模型类代码：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
class AreaInfo(models.Model):
"""地区模型类"""
name = models.CharField(max_length = 50)
pid = models.ForeignKey('self', related_name = 'areas',null=True, blank=True, on_delete = models.SET_NULL)
def __str__(self):
return self.name
class Meta:
db_table = 'areainfo'
verbose_name = '地区信息'
verbose_name_plural = verbose_name
class HeroInfo(models.Model):
"""任务信息模型类"""
name = models.CharField(max_length = 50)
# on_delete 表示关联的外键表删除数据时，该条数据不变，外键置为空
province = models.ForeignKey(AreaInfo, null=True, blank=True, on_delete = models.SET_NULL)
city = models.ForeignKey(AreaInfo, related_name = 'areainfo', null=True, blank=True, on_delete = models.SET_NULL)
country = models.ForeignKey(AreaInfo, related_name = 'areainfos', null=True, blank=True, on_delete = models.SET_NULL)
def __str__(self):
return self.name
class Meta:
db_table = 'heroinfo'
verbose_name = '人物信息'
verbose_name_plural = verbose_name在一个模型类中，两个外键关联同一个模型类，要使用related_name进行设置,否则会报错。related_name 不能相同，否则迁移数据库会出错，反向查询名称重复。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
然后进行数据库迁移，在数据库中导入地区信息，为后续使用做准备。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
使用数据库时，不要忘记在settings.py中修改数据库配置。同时使用时，要在应用的__init__.py文件中，添加以下两行代码：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
import pymysql
pymysql.install_as_MySQLdb因为在MySQLdb是python连接MySQL的模块，在py2中使用，py3中没有MySQLdb,所以py3要安装pymysql，并进行以上设置。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
二、以上步骤完成之后进行第二部，注册模型类文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
@admin.register(AreaInfo)
class AreaAdmin(admin.ModelAdmin):
list_display = ('name', 'pid') # 这里要使用元组或者列表
@admin.register(HeroInfo)
class HeroAdmin(admin.ModelAdmin):
list_display = ('name', 'province', 'city', 'country')
change_form_template = 'area.html'在这里用到了change_form_template，可以自定义访问路径，改变django默认的路径文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
三、在template中新建一个文件admin，在admin中新建一个area.html页面，将django 中的 change_form.html内容拷贝过来。
文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
后面写三级联动的js要在这里，改变django默认的路径，读取的也是该页面，上面在admin中已经进行了设置。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
四、以上步骤完成以后就可以开始写三级联动的js和view。文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
1.html中添加js代码如下：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
发送ajax请求，获取并展示省份信息文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
$.get('/areas/choose/province/',function(p_info){
var province_info = $('#id_province').empty().append('<option value>'+'---------'+'</option>');
$.each(p_info.p_lists,function(i,province){
province_info.append('<option value="'+province.p_id+'">'+province.p_name+'</option>')
});url配置： url(r'^choose/province/$', views.choose_province),文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
视图代码：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
def choose_province(request):
"""查询省"""
provinces = AreaInfo.objects.filter(pid=None)
p_lists = [{"p_id": province.id, "p_name": province.name} for province in provinces]
p_info = {"p_lists":p_lists}
return JsonResponse(p_info, safe=False)这里注意，要设置safe=False，否则会报错：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
TypeError: In order to allow non-dict objects to be serialized set the safe parameter to False.文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
2.发送ajax请求，获取并展示城市信息文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
$.get('/areas/choose/province/',function(p_info){
var province_info = $('#id_province').empty().append('<option value>'+'---------'+'</option>');
$.each(p_info.p_lists,function(i,province){
province_info.append('<option value="'+province.p_id+'">'+province.p_name+'</option>')
});
$('#id_province').change(function(){
p_id = $(this).val();
$.get('/areas/choose/city/',{'p_id':p_id},function(c_info){
var city_info = $('#id_city').empty().append('<option value>'+'---------'+'</option>');
$.each(c_info.c_lists,function(i,city){
city_info.append('<option value="'+city.c_id+'">'+city.c_name+'</option>')
})
})
});URL配置：url(r'^choose/city/$', views.choose_city),文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
视图代码：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
def choose_city(request):
"""查询市"""
p_id = request.GET.get('p_id')
print(p_id,'--------')
citys = AreaInfo.objects.filter(pid=p_id)
c_lists = [{"c_id": city.id, "c_name": city.name} for city in citys]
print(c_lists[0:5])
c_info = {"c_lists": c_lists}
return JsonResponse(c_info, safe=False)
3.发送ajax请求，获取并展示区信息
$.get('/areas/choose/province/',function(p_info){
var province_info = $('#id_province').empty().append('<option value>'+'---------'+'</option>');
$.each(p_info.p_lists,function(i,province){
province_info.append('<option value="'+province.p_id+'">'+province.p_name+'</option>')
});
$('#id_province').change(function(){
p_id = $(this).val();
$.get('/areas/choose/city/',{'p_id':p_id},function(c_info){
var city_info = $('#id_city').empty().append('<option value>'+'---------'+'</option>');
$.each(c_info.c_lists,function(i,city){
city_info.append('<option value="'+city.c_id+'">'+city.c_name+'</option>')
})
})
});
$('#id_city').change(function(){
c_id = $(this).val();
$.get('/areas/choose/area/',{"c_id": c_id},function(a_info){
var area_info = $('#id_country').empty().append('<option value>'+'---------'+'</option>');
$.each(a_info.a_lists,function(i,area){
area_info.append('<option value="'+area.a_id+'">'+area.a_name+'</option>')
});
});
});
});URL配置：url(r'^choose/area/$', views.choose_area),文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
视图代码：文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html
def choose_area(request):
"""查询区"""
c_id = request.GET.get('c_id')
print(c_id,'=======')
areas = AreaInfo.objects.filter(pid=c_id)
print(areas)
a_lists = [{"a_id": area.id, "a_name": area.name } for area in areas]
a_info = {"a_lists": a_lists}
print(a_info)
return JsonResponse(a_info, safe=False)文章源自菜鸟学院-https://www.cainiaoxueyuan.com/bc/28186.html