title: How to sort and filter a WinJS custom data source which implements IListDataAdapter?
body: <p>I've created a custom data source for a ListView which implements the IListDataAdapter. The data comes from a couple different web services, and requires multiple asynchronous calls to get fully populated. The data populates correctly, and the ListView exhibits the nice "infinite scroll" functionality, loading new pages of data as needed.</p>
  
  <p>I'm now trying to filter the data on a couple different properties. I have a checkbox and a drop down list, both of which have events which fire correctly. These events should call the updateLayout method...but for some reason that method ends up being undefined.</p>
  
  <pre><code>    checkBoxClick: function (eventObject) {
          this.updateLayout(document, Windows.UI.ViewManagement.ApplicationView.value);
      },
  
      dropDownListValueChange: function (eventObject) {
          this.updateLayout(document, Windows.UI.ViewManagement.ApplicationView.value);
      },
  </code></pre>
  
  <p>I'm hoping that somebody out there has a project that uses a custom data source and supports both sorting AND filtering, and would be willing to share that code with the class.</p>