windows-phone-7 – Windows Phone上的自定义动态磁贴渲染问题(7

我遇到的问题是,如果用户点击按钮然后快速点击手机的后退按钮,实时图块有时将无法正常呈现.这个问题很少发生,但确实发生了,当它发生时它看起来很糟糕……

我实现实时磁贴的方法是,创建一个与实时磁贴完全相同的用户控件,然后将其保存到隔离存储中.然后检索它并将其存储在FliptileData对象中.最后,我在ShellTile上调用Update方法.请参阅以下代码片段以演示该过程.

// the function that saves the user control to isolated storage
    public Uri SaveJpegToIsolatedStorage(FrameworkElement tile,string suffix,int tileWidth = 336,int tileHeight = 336)
    {
        var bmp = new WriteableBitmap(tileWidth,tileHeight);

        // Force the content to layout itself properly
        tile.Measure(new Size(tileWidth,tileHeight));
        tile.Arrange(new Rect(0,tileWidth,tileHeight));

        bmp.Render(tile,null);
        bmp.Invalidate();

        // Obtain the virtual store for the application
        IsolatedStorageFile myStore = IsolatedStorageFile.GetUserStoreForApplication();
        using (IsolatedStorageFileStream fileStream = new IsolatedStorageFileStream(IsolatedStorageFileName + suffix,FileMode.Create,myStore))
        {
            try
            {
                bmp.SaveJpeg(fileStream,tileHeight,100);
            }
            catch (Exception)
            {
                return null;
            }
        }

        return new Uri("isostore:/" + IsolatedStorageFileName + suffix,UriKind.Absolute);
    }

    // save the user control to isolated storage and prepare the FlipTileData object
    wideFrontTileImage = SaveJpegToIsolatedStorage((UserControl)this.WideFrontTile,"_wide_front",691);
    var flipTileData = new FlipTileData();
    flipTileData.WideBackgroundImage = wideFrontTileImage;
    return flipTileData;

    // update the live tile
   var shellTile = ShellTile.ActiveTiles.FirstOrDefault();
   shellTile.Update(customTile.GetFlipTileData(data.UndoneMemosCount == "0" && data.TotalMemosCount == "0"));

我认为造成这一切的原因是,当用户太快地单击“后退”按钮时,操作系统会终止应用程序中运行的所有进程,并且当时没有完成呈现.我在想是否有办法知道渲染何时完成,所以我可以取消后退按钮并等到它完成然后手动退出应用程序.但我简直不知道如何……

任何有关这一方面的帮助将不胜感激！