title: How to enable select all feature in material-ui/SelectField component?
body: <p><a href="https://v0.material-ui.com/#/components/select-field" rel="nofollow noreferrer">Document Link</a>
  I am following the above document Link for implementing the Select-field component.
  I didnot find the proper document for select all in this component.</p>
  
  <p>Import statement for component</p>
  
  <pre><code>import SelectField from 'material-ui/SelectField'; 
  </code></pre>
  
  <p>Component code: </p>
  
  <pre><code>&lt;SelectField
      className="search_items"
      multiple={true}
      hintText="Select Item"
      value={values}
      onChange={this.handleChange} &gt;
      {this.menuItems(values)}
   &lt;/SelectField&gt;
  </code></pre>
  
  <p>menuItems Function:</p>
  
  <pre><code>menuItems(values) {
       return unique &amp;&amp; unique.map((name) =&gt; (
          &lt;MenuItem
              key={name}
              insetChildren={true}
              checked={values &amp;&amp; values.indexOf(name) &gt; -1}
              value={name}
              primaryText={name &amp;&amp; name.concat('(').concat(sectors.filter(i =&gt; i === name).length).concat(')')}
          /&gt;
      ));
  }
  </code></pre>
  
  <p>OnChange Function :</p>
  
  <pre><code>handleChange(event, index, values) {
      this.setState({ values })
  }
  </code></pre>
  
  <p>How to enable select all option for all the items to be selected.
  Thanks in advance</p>