Dynamic class name for a div after an iron-ajax
<p>I need to set the name of a class dynamically executing a function after an iron-ajax request.</p>

<p>In the template section of my element I have:</p>

<pre><code>&lt;div class="{{dynamicClass}}"&gt;&lt;/div&gt;
</code></pre>

<p>I have defined this property like this: </p>

<pre><code>Polymer({
        is: "fila-contenido"
        ,
        properties: {
            dynamicClass: {
                type: Number
            }
        }
        ...
</code></pre>

<p>I have an on-response function executed when iron-ajax responses:</p>

<pre><code>_onResponse: function (e) {
            var nro = e.detail.response.length;

            switch(nro){
                case 2:
                    this.dynamicClass = "class2";
                    break;

                case 3:
                    this.dynamicClass = "class3";
                    break;
                ...
            }

        }
</code></pre>

<p>This function set the name of the class correctly.</p>

<p>The problem is the output is not showing the dynamic class but:</p>

<pre><code>&lt;div class="style-scope fila-contenido"&gt;&lt;/div&gt;
</code></pre>

<p>How may I do this?
Thanks!</p>