Windows Phone 磁贴

因磁贴默认属性无法满足需求，所以就在背景图片上面下手。把所有要显示到磁贴上面的数据，布局等用后台代码写，布局成“XAML”，然后把生成的“XAML”数据存储为PNG图片或者JPG图片，再把生成的图片任务磁贴的背景图片，来满足需求。

var tileData = new StandardTileData()
            {
                Title = string.Empty,
                BackgroundImage = new Uri(this.CreateBackground()),
                Count = 0,
                BackTitle = string.Empty,
                BackBackgroundImage = new Uri(this.CreateBackBackground()),
                BackContent = string.Empty
            };

private string CreateBackground_MainAppClassical()
        {
            Grid grid = new Grid
            {
                Width = 210,
                Height = 210
            };

            ........
            
            TextBlock txt_day = new TextBlock
            {
                Text = DateTime.Now.Day.ToString(),
                FontSize = 90,
                Foreground = new SolidColorBrush(Colors.White),
                VerticalAlignment = VerticalAlignment.Bottom,
                Margin = new Thickness(0, 0, 0, -24)
            };
            sp.Children.Add(txt_day);
            grid.Children.Add(sp);
            grid.Arrange(new Rect(0d, 0d, 210, 210));
            WriteableBitmap wbmp = new WriteableBitmap(grid, null);
            string path = "Shared/ShellContent/tiles/tile_main.png";
            StoragePNGToIS(path, wbmp);
            return "isostore:/" + path;
        }        

/// <summary>
        /// 存储Tile图片到IS (JPG)
        /// </summary>
        public void StorageJPGToIS(string path, WriteableBitmap wbmp)
        {
            string directory = "Shared/ShellContent/tiles";
            using (IsolatedStorageFile storageFile = IsolatedStorageFile.GetUserStoreForApplication())
            {
                if (!storageFile.DirectoryExists(directory))
                {
                    storageFile.CreateDirectory(directory);
                }
                using (IsolatedStorageFileStream stream = storageFile.OpenFile(path, FileMode.Create))
                {
                    wbmp.SaveJpeg(stream, wbmp.PixelWidth, wbmp.PixelHeight, 0, 100);
                }
            }
        }

        /// <summary>
        /// 存储Tile图片到IS (PNG)
        /// </summary>
        private void StoragePNGToIS(string path, WriteableBitmap wbmp)
        {
            string directory = "Shared/ShellContent/tiles";
            using (IsolatedStorageFile storageFile = IsolatedStorageFile.GetUserStoreForApplication())
            {
                if (!storageFile.DirectoryExists(directory))
                {
                    storageFile.CreateDirectory(directory);
                }
                using (IsolatedStorageFileStream fileStream = storageFile.OpenFile(path, FileMode.Create, FileAccess.Write))
                {
                    using (StreamWriter writer = new StreamWriter(fileStream))
                    {
                        PngEncoder encoder = new PngEncoder();
                        encoder.Encode(wbmp.ToImage(), writer.BaseStream);
                    }
                }
            }
        }

存储PNG图片的代码可参考：http://www.win7soft.com/wp/jc/jiaocheng_12498.html

注： 开发环境为VS2012+SDK8.0  开发WP7.X项目

1、更新、创建磁贴的时候，需要使用this.Dispatcher.BeginInvoke()处理线程问题。

2、如果使用的Toolkit里面的ContextMenu弹出菜单固定磁贴的话，ContextMenu的IsZoomEnabled="False"属性需要去掉。

以上两点可能会导致在存储为PNG图片的时候，布局混乱的情况，暂时这些发现，没有找到具体原因。

3、磁贴翻转：

同时设置了背景和背面背景时，磁贴就会有翻转的情况，即：BackgroundImage = new Uri(), BackBackgroundImage = new Uri()

创建的时候，将背面背景设置为Null时，则不会有翻转，即：BackgroundImage = new Uri(), BackBackgroundImage = null

设置了背面背景图后，把磁贴更新为不要背景，即不翻转：BackgroundImage = new Uri(), BackBackgroundImage = new Uri()    ==》 BackgroundImage = new Uri(), BackBackgroundImage = null，此时的要求是把翻转的磁贴更新为不翻转，但是这个时候磁贴同样会翻转。

这个时候需要将BackBackgroundImage = new Uri("", UriKind.Relative)，设置为一个不存在的相对路径，才会有效果。

磁贴翻转可参考：http://www.haogongju.net/art/1676949