javascript - 在 Backbone 中跨不同类触发和监听事件 - 在 CoffeeScript 中

Question

基本上我是 Backbone 的新手。从我看来，我正在更改我的集合中名为“限制”的属性。然后我尝试触发一个事件(当属性刚刚更改时)，允许我监听该事件并执行其他操作。

但是，当某些内容发生更改时从我的集合中触发事件，并在发生更改时监听该更改是行不通的。我认为这与 View 和集合之间的通信有关。任何帮助将不胜感激!谢谢

触发事件的代码(在我的集合中)是:

@trigger("change") #TRIGGER THE EVENT

更改我的集合中的属性的代码(有效)是:

@Properties.attr("limit", "1000") #Change the limit attr to "1000"

监听变化的代码(不起作用)是:

@Properties.on("change", ->
     alert("Attribute has been changed!")
)

完整代码是:

class PropertyCollection extends Backbone.Collection
        model: Property

        constructor: ->
            super

        initialize: ->
            @_attr = {}

        #Function to change attribute of collection 
        attr: (prop, value) ->
            if value is undefined
                @_attr[prop]
            else
                @_attr[prop] = value
                @trigger("change") #TRIGGER THE EVENT

        limit: "0" #Attribute - default is set to 0



    class HomeView extends Backbone.View
        constructor: ->
            super

        initialize: ->
                @Properties = new PropertyCollection

                @Properties.attr("limit", "1000") #Change the limit attr to "1000"

                #Listen for the change
            @Properties.on("change", ->
                 alert("Attribute has been changed!")
            )

        template: _.template($('#home').html())

        render: ->
            $(@.el).html(@template)

Answer 1

您在做出更改后注册监听该更改

更改属性->触发事件->无人监听->注册监听

所以改变这个:

initialize: ->
  @Properties = new PropertyCollection

  @Properties.attr("limit", "1000") #Change the limit attr to "1000"

  #Listen for the change after the firing of the change (why?!!!)
  @Properties.on("change", ->
    alert("Attribute has been changed!")
  )

到此

initialize: ->
  @Properties = new PropertyCollection

  #Listen for the change BEFORE you make it (yes yes yes!!!)
  @Properties.on("change", ->
    alert("Attribute has been changed!")
  )

  @Properties.attr("limit", "1000") #Change the limit attr to "1000"

希望这有帮助!