我正在尝试使用Backbone.Relational在我的应用中设置一些关联。
基本上我有Backbone Search
和Service
模型。搜索具有ServiceList
集合,其中包含许多服务。
但是,我似乎无法从服务初始化程序中访问父搜索。当我尝试记录父搜索时,我得到null
。谁能看到我做错了什么?
我的搜索模型设置如此(代码可能有语法错误,我正在动态地从coffeescript翻译):
var Search = new Backbone.RelationalModel({
urlRoot: '/searches',
relations: [{
type: Backbone.HasMany,
key: 'services',
relatedModel: 'Service',
collectionType: 'ServiceList',
reverseRelation: {
key: 'search'
}
}],
initialize: function(options) {
// => Search "has services:", ServiceList
console.log this, "has services:", @get('services');
}
});
var Service = new Backbone.RelationalModel
initialize: function() {
// => Service "in" null
console.log this, "in", @get('search');
}
});
或者如果您更喜欢CoffeeScript:
class Search extends Backbone.RelationalModel
urlRoot: '/searches'
relations: [
type: Backbone.HasMany
key: 'services'
relatedModel: 'Service'
collectionType: 'ServiceList'
reverseRelation:
key: 'search'
]
initialize: (options) ->
// => Search "has services:", ServiceList
console.log this, "has services:", @get('services')
class Service extends Backbone.RelationalModel
initialize: ->
// => Service "in" null
console.log this, "in", @get('search')
答案 0 :(得分:10)
简答
您只是无法访问Service的initialize方法中的反向关系值。
反向关系的值在初始化完成后设置。
更长的答案
假设这个javascript:
Search = Backbone.RelationalModel.extend({
urlRoot: '/searches',
relations: [{
type: Backbone.HasMany,
key: 'services',
relatedModel: 'Service',
reverseRelation: {
key: 'search'
}
}],
initialize: function(options) {
console.log(this, "has services:", this.get('services'));
}
});
Service = Backbone.RelationalModel.extend({
initialize: function() {
console.log(this, "in", this.get('search'));
}
});
使用相关服务创建新的搜索模型时:
s1 = new Search({name:"Some Search",services:[{name:"service1"},{name:"service2"}]});
将要发生的事情是:
new Service model created (for service1) - name set to "service1"
(but, since what got passed to the model for properties is {name:"service1"}
you can see how this model cannot know its reverse relation yet.)
new Service model created (for service2) - name set to "service2"
(same as above)
new Search model created (for 'some search')
name set to 'some search'
service1 Service model added to Search.services
(triggers 'update:search' event on Service1 model)
service2 Service model added to Search services
(triggers 'update:search' event on Service2 model)
直到将service1和service2服务模型添加到Search.services集合中,才设置service1.search和service2.search上的反向关系。
这是一个JS小提琴,显示了控制台中的操作顺序:http://jsfiddle.net/MNh7N/6/