How to load partials / views / templates dynamical

问题:

So I have the following setup.

On the main page, a list of generators is being displayed based on a list coming from a model using fixture data.

Now when one of the generator links is clicked, a new page is shown with some input fields that are dynamically generated based on that fixture data.

Until this point everything works perfectly.

Now when I change the input field's value in the generator page (after selecting one of the generators) to see the changes being updated in some sort of a preview div just below my input fields, it is easy. I can use {{generatorFields.0.value}} to bind the first input field, .1., and so on until I bind all of them.

But as you can imagine, each generator has its own format and its own input fields, and I want to create a new .hbs file for each and every one of them and then pass that file into the generator page to show the preview.

I solved 0.1% of the problem with a partial. In the generator.hbs file I entered {{partial "generator-1"}} and this loads my _generator-3.hbs file that contains that {{generatorFields.0.value}} bind, and it works. But that partial is not dynamic; I need to load a different partial each time I use a different generator. How can I achieve this?

How can I pass the partial name dynamically or load a template based on the model data that I have?

The code used so far is below:

idex.hbs looks like this:

 <table class="table table-hover">
            <thead>
                <tr>
                    <th>#</th>
                    <th>Generator name</th>
                    <th>Action</th>
                </tr>
            </thead>
            <tbody>
                {{#each model}}
                <tr>
                    <td>{{id}}</td>
                    <td>{{title}}</td>
                    <td>{{#linkTo 'generator' this classNames="btn btn-mini pull-right"}}Create file{{/linkTo}}</td>
                </tr>
                {{/each}}
                </tbody>
        </table>

generator.hbs

{{#each generatorFields}}
<div class="row-fluid">
    <div class="span4">{{name}}</div>
    <div class="span8">{{view Ember.TextField valueBinding='value' class='span12' placeholder='Type value here…'}}</div>
</div>
{{/each}}

{{partial "generator-1"}}

_generator-1.hbs

<h1>Project: {{generatorFields.0.value}}</h1>

app.js

App.Store = DS.Store.extend({
    revision: 13,
    adapter: 'DS.FixtureAdapter'
});

App.Router.map(function () {
    this.resource('index', { path: '/' });
    this.resource('generator', {path: '/generator/:generator_id'});
});

App.IndexRoute = Ember.Route.extend({
    model: function () {
        return App.Generator.find();
    }
});

App.Generator = DS.Model.extend({
    title: DS.attr('string'),
    templateName:  DS.attr('string'),
    generatorFields: DS.attr('generatorFields')
});


// Fixture data

DS.RESTAdapter.registerTransform('generatorFields', {
    serialize: function(serialized) {
        return Em.none(serialized) ? {} : serialized;
    },
    deserialize: function(deserialized) {
        return Em.none(deserialized) ? {} : deserialized;
    }
});

App.Generator.FIXTURES = [{
    id: 1,
    title: "test 1",
    generatorFields: [
        {id: 1, name: "name 1", value: ""}
    ],
    templateName: "generator-1"
}, {
    id: 2,
    title: "test 2",
    generatorFields: [
        {id: 1, name: "name 1", value: ""},
        {id: 2, name: "name 2", value: ""},
    ],
    templateName: "generator-2"
}];

回答1:

You can create a dynamic partial helper that uses the passed in name to render with the {{partial}} helper.

Ember.Handlebars.helper('dynPartial', function(name, options) {
  return Ember.Handlebars.helpers.partial.apply(this, arguments);
});

Then use this dynamic partial, {{dynPartial}} instead.

{{#each item in controller}}
  {{dynPartial item.templateName}}
{{/each}}

For a generator with templateName of generator-1. This would render with the partial _generator-1. Note that the name of the template's id/data-template-name must begin with an underscore.

回答2:

You should be able to simply place your dynamic partial variable within the partial helper.

{{#each item in controller}}
    {{partial item.templateName}}
{{/each}}

As @darshan-sawardekar pointed out if you have a generator with templateName of generator-1it would render the partial _generator-1.

回答3:

While @Darshan's answer is simpler than the below and will work in many cases, I just ran into an issue where transitioning to a same route with a different model causes the partial to not re-render if the second model's partial name is the same as the first's (bug in ember?). Setting up a view that watches the model fixes this.

App.FooDynamicLayout = Ember.View.extend
  rerenderOnModelChange: (->
    @rerender()
  ).observes('model')

And call it with:

view App.FooDynamicLayout templateName=dynamicTemplateName model=model

回答4:

@KamrenZ already mentioned this but I figured I'd cite chapter and verse for those looking into this. More recent versions of Ember gracefully accept bound property names and use them in the partial helper:

http://ember-doc.com/classes/Ember.Handlebars.helpers.html#method_partial

BOUND TEMPLATE NAMES The parameter supplied to partial can also be a path to a property containing a template name, e.g.:

{{partial someTemplateName}}

The above example will look up the value of someTemplateName on the template context (e.g. a controller) and use that value as the name of the template to render. If the resolved value is falsy, nothing will be rendered. If someTemplateName changes, the partial will be re-rendered using the new template name.