如何在一个主干视图中多次调用render函数？

Question

So essentially, I want to display 3 different views depending on what "wheel" we're looking at. So I create 3 different JST templates. The initial default view that shows is the Cars/first_wheel template. When I click on a button with id of #next-step, the render function is triggered as I see the alert(wheel) message box. But the call to " $(@el).html(...)" doesn't change the contents of what's displayed...Why is that?

Backbone.View.prototype.eventAggregator = _.extend({}, Backbone.Events);

class Wheel.Views.CarsFirstwheel extends Backbone.View

  initialize: ->
    _.bindAll(this, 'render','nextwheel', 'prevwheel');
    @collection = new Wheel.Collections.Cars
    Car_state = new Wheel.Models.Car(
      current_wheel: 0
      next_wheel: 1
      prev_wheel: 2
      current_view: ""
    )
    @collection.add(Car_state)
    @eventAggregator.bind("call_render", @render);

  wheel1_template: JST['Cars/first_wheel'],
  wheel2_template: JST['Cars/second_wheel']
  wheel3_template: JST['Cars/third_wheel']

  render: ->
    wheel = @collection.at(0).get 'current_wheel'
    switch 0
      when 0
        $(@el).html(@wheel1_template())
        alert(wheel)
      when 1
        $(@el).html(@wheel2_template())
        alert(wheel)
      when 2
        $(@el).html(@wheel3_template())
        alert(wheel)
    this       

  nextwheel: ->
    Car_state = @collection.at(0)
    count = ((Car_state.get 'current_wheel')+1)%3
    Car_state.set 
      current_wheel: count
    Car_state.save
    @collection.fetch
    @eventAggregator.trigger("call_render")

  prevwheel: ->
    Car_state = @collection.at(0)
    count = (Car_state.get 'current_wheel'-1)%3
    Car_state.set 
      current_wheel: count
    Car_state.save
    @collection.fetch

  events: ->
    'click #next-wheel': 'nextwheel'

Answer 1

Never mind - I forgot to change the 0 in "switch 0" back to wheel. When I do that, all works.