Backbone view el not defined

问题

I have this code -

class TableManager 
  tables : {}
  tableViews :{}
  nextId : 0
  rootEl : 'body'
  addTable:(json,el)->
    newTableModel = new TableModel(json,@nextId)
    newTableModel
    @tables[@nextId] = newTableModel
    el = "#table1"
    newView = new TableView({model : newTableModel, columns : json["Columns"], el : el, id : @nextId})
    @tableViews[@nextId] = newView
    newTableModel.renderModel()
    @nextId++

class TableView extends Backbone.View
  tableId : ''
  columns : ''
  thead : ''
  tbody : ''
  input : ''
  rows : ''
  inputId : ''
  typingTimer : ''
  doneTypingInterval : 2000
  el : '#table1'
  initialize:()->
    @model.bind "render", @render 
    @tableId = "resultsTable#{@options.id}"
    @inputId = "filterInput#{@options.id}"
    @columns = @options.columns

  render:()=>
    console.log "EL"
    console.log $(@el)
    console.log @el

The console.log @el is always undefined. I don't know why, I'm setting this.el correctly I thought? Is it because render is being called as a result of an event firing?

回答1:

You don't have an id="table1" element in the DOM when you instantiate your TableView. For example, if you do this without anything in the DOM:

class V extends Backbone.View
    el: '#no-such-element'
    render: => console.log @el

v = new V
v.render()

you'll get an undefined in the console.

Demo: http://jsfiddle.net/ambiguous/ne39B/

If you want Backbone to create an id="table1" element then you'll need to use different properties to tell Backbone to do so; the View#el documentation states:

this.el is created from the view's tagName, className, id and attributes properties,

So you have some options:

1. Make sure #table1 is in the DOM when you create the view.
2. Pass the el to the view when you instantiate it: v = new TableView(el: some_dom_object).
3. Use the tagName, className, id, and attributes view attributes to get Backbone to construct the appropriate DOM element for you.

Also, Backbone won't add the view's el to the DOM for you, even if Backbone builds the view's el you'll have to add it to the DOM yourself.

来源：https://stackoverflow.com/questions/17479583/backbone-view-el-not-defined