骨干木偶，两次渲染复合视图？

Question

I have this issue that prints user data twice, this is the code:

window.UserData = {}
UserData.Model = Backbone.Model.extend();
UserData.Collection = Backbone.Collection.extend({
  url: '/test.php?c=userData',
  model: UserData.Model,
  parse: function (response) {
    return response.data;
  }
});
UserData.View = Backbone.Marionette.CompositeView.extend({
  tagName: 'span',
  template: Handlebars.compile($('#user-data-template').html())
});
BaseApp.Layout = Backbone.Marionette.Layout.extend({
  template: Handlebars.compile($('#base-layout-template').html()),
  regions: {
    'region_user_data': '#user_data_reg'
  },
  initialize: function () {
    _.bindAll(this);
  },
  onRender: function () {
    var self = this;
    var c = new UserData.Collection();
    c.fetch({
      success: function () {
        var ud = new UserData.View({
          collection: c
        });
        self.region_user_data.show(ud);
      }
    });
  }
});

this BaseApp Layout is being rendered once on a region (in body).

This is the template:

<script id='user-data-template' type='text/x-handlebars-template'>
    <a href="#" id="logout"> Logout </a> Hola {{uname}}
</script>

<script id='base-layout-template' type='text/x-handlebars-template'>
    base page layout
    <div id="user_data_reg" class="user_data_reg"></div>
</script>

this is what is being shown in the browser (chrome):

Logout Hola Logout Hola 14

As you can see it displays the user layout twice but the first time does not displays the uname, it is kind of weird because in chrome I have this:

child {models: Array[0], length: 0, _byId: Object, 
constructor: function, url: "http://localhost/test.php?c=userData"…}

the model is being displayed only 1 and what it does is that prints twice content.

Also when I fetch the collection data I do this:

c.fetch({
  success: function () {
    var ud = new UserData.View({
      collection: c
    });
    self.region_user_data.show(ud);
    console.log("print xx");
  }

and it only logs "print xx" only once & not twice as I expected.

Why am I getting double userData content even if the collection is fetching only a single model, why is this happening? Regards.

Answer 1

This was an issue with the view type, instead of using "CompositeView" I switched to ItemView and the problem went away. I guess Marionette forces to use ItemView for single data.