private async void navigationHelper_LoadState(object sender, LoadStateEventArgs e)
{
this.DefaultViewModel["Commands"] = this;
var storage = new MenuCardStorage();
MenuCardRepository.Instance.InitMenuCards(new ObservableCollection<MenuCard>(
await storage.ReadMenuCardsAsync()));
this.DefaultViewModel["Items"] = MenuCardRepository.Instance.Cards;
}
/// <summary>
/// 保留与此页关联的状态，以防挂起应用程序或
/// 从导航缓存中放弃此页。 值必须符合
/// <see cref="SuspensionManager.SessionState"/> 的序列化要求。
/// </summary>
///<param name="sender">事件的来源；通常为 <see cref="NavigationHelper"/></param>
///<param name="e">提供要使用可序列化状态填充的空字典
///的事件数据。</param>
///
// 退出页面时会调用 保存添加的Card
private async void navigationHelper_SaveState(object sender, SaveStateEventArgs e)
{
var mc = new MenuCard
{
Title = info.Title,
Description = info.Description,
Image = info.Image,
ImagePath = info.ImageFileName
};
MenuCardRepository.Instance.Cards.Add(mc);
var storage = new MenuCardStorage();
await storage.WriteMenuCardsAsync(MenuCardRepository.Instance.Cards.ToList());
}
private async void OnUploadImage(object sender, RoutedEventArgs e)
{
// 定义选择器
var filePicker = new FileOpenPicker();
filePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
filePicker.FileTypeFilter.Add(".jpg");
filePicker.FileTypeFilter.Add(".png");
StorageFile file = await filePicker.PickSingleFileAsync();
if (file == null) return;
var stream = await file.OpenAsync(FileAccessMode.Read);
var image = new BitmapImage();
image.SetSource(stream);
image.ImageOpened += async (sender1, e1) =>
{
if (image.PixelHeight > image.PixelWidth)
{
image.DecodePixelHeight = 900;
}
else
{
image.DecodePixelWidth = 900;
}
stream.Seek(0);
var imageStorage = new MenuCardImageStorage();
var storage = new MenuCardStorage();
info.ImageFileName = string.Format("{0}.jpg", Guid.NewGuid().ToString());
await imageStorage.WriteImageAsync(stream, info.ImageFileName);
};
image.ImageFailed += (sender1, e1) =>
{
string s = e1.ErrorMessage;
};
info.Image = image;
}
private static async Task InitSampleDataAsync()
{
var storage = new MenuCardStorage();
var imageStorage = new MenuCardImageStorage();
if (await storage.IsRoamingFolderEmpty())
{
List<MenuCard> menuCards = MenuCardRepository.GetSampleMenuCards().ToList();
foreach (var card in menuCards)
{
RandomAccessStreamReference streamRef =
RandomAccessStreamReference.CreateFromUri(new Uri(card.ImagePath));
using (IRandomAccessStreamWithContentType stream =
await streamRef.OpenReadAsync())
{
card.ImagePath = string.Format("{0}.png", Guid.NewGuid());
await imageStorage.WriteImageAsync(stream, card.ImagePath);
}
}
await storage.WriteMenuCardsAsync(menuCards);
}
}