//Private
        private static async Task LaunchAppPageAsync(string packageFamilyName, AppPageLaunchType launchType)
        {
            if (string.IsNullOrWhiteSpace(packageFamilyName))
            {
                packageFamilyName = Package.Current.Id.FamilyName;
            }
            string format   = launchType == AppPageLaunchType.ProductDetailsPage ? STOREURI_PDP_FORMAT : STOREURI_REVIEW_FORMAT;
            string storeURI = string.Format(format, packageFamilyName);

            await LaunchUriAsync(storeURI);
        }
 /// <summary>
 /// Launches the specified App page using the specified launch type.
 /// </summary>
 public static async void LaunchAppPage(string packageFamilyName, AppPageLaunchType launchType)
 {
     await LaunchAppPageAsync(packageFamilyName, launchType);
 }
 //APPS PAGES
 /// <summary>
 /// Launches the current App page using the specified launch type.
 /// </summary>
 public static async void LaunchAppPage(AppPageLaunchType launchType)
 {
     await LaunchAppPageAsync(string.Empty, launchType);
 }