windows-8 – 在后台任务中访问Javascript Metro应用程序的Index

我正在设置这样的任务：

var builder = new Windows.ApplicationModel.Background.BackgroundTaskBuilder();
        builder.name = taskName;
        builder.taskEntryPoint = "jstaskbackgroundTask.js";

        //Run every 8 hours if the device is on AC power
        var trigger = new Windows.ApplicationModel.Background.MaintenanceTrigger(480,false);
        builder.setTrigger(trigger);

        var task = builder.register();

任务看起来像这样：

(function () {
    "use strict";

    var backgroundTaskInstance = Windows.UI.WebUI.WebUIBackgroundTaskInstance.current;
    var cancel = false;

    function doWork() {
        var key = null,settings = Windows.Storage.ApplicationData.current.localSettings;

        //todo access db and update tile

        close();
    }

    if (!cancel) {
        doWork();
    } else {
        close();
    }

    function onCanceled(cancelSender,cancelReason) {
        cancel = true;
    }

    backgroundTaskInstance.addEventListener("canceled",onCanceled);

})();

该任务似乎工作正常,但如果我可以访问数据库(或任何应用程序资源),我无法解决.这种事情是否可能,如果是这样,我错过了什么？