AnnotatedDocumentViewer批注文档浏览

1、实现功能：

1. 文档右键菜单创建和删除批注命令
2. ListBox显示批注创建时间（排序）和内容
3. 选定一个批注，流文档显示到对应批注锚定

2、关注词：

1. 批注XML架构及内容组织：
2. AnnotationService+AnnotationStore+IAnchorInfo
3. Convert.FromBase64String+XamlReader.Load+TextRange
4. AnnotationService.Enable（AnnotatinoStore）

3、静态组织：
界面xaml:

<!-- Annotations List -->
<ListBoxName="annotationsListBox"Grid.Row="2"SelectionChanged="annotationsListBox_SelectionChanged"ItemsSource="{Binding}"Template="{StaticResource AnnotationsListTemplate}"ItemTemplate="{StaticResource AnnotationDataTemplate}" />

ListBox模板Template:简单设置竖滚动条+StackPanel容器

<!--To Replace ListBox Template with Template that Allows TextWrapping andalso provides a vertical scrollbar when the wrapped text extends below the bottom of the list box -->
<ControlTemplate x:Key="AnnotationsListTemplate"><ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Disabled" ><StackPanel IsItemsHost="True" /></ScrollViewer>
</ControlTemplate>

ListItem的数据模板：

1. TextBlock内容中[]里面绑定批注数据区AnnotationStore的时间属性CreationTime,
2. 其后TextBlock.Text绑定到批注数据区AnnotationStore的（AnnotationResource)货物Cargos[1]的内容Content[0]的(string)InnerText

<!-- Data Template for Annotation Item that shows when an annotation wascreated, and what data the annotation contains.  -->
<DataTemplate x:Key="AnnotationDataTemplate"><TextBlock Margin="5" TextWrapping="Wrap"><TextBlock FontWeight="Bold" TextWrapping="Wrap">[<TextBlock Text="{Binding Path=CreationTime}" />]</TextBlock><TextBlockText="{Binding Path=Cargos[1].Contents[0].InnerText,Converter={StaticResource AnnotationDataConverter}}"TextWrapping="NoWrap" /></TextBlock>
</DataTemplate>

绑定转换string》TextRange.Text(Xml包含的Xaml数据转换为文本Text格式数据：

1. 把Base64格式的string 使用Convert.FromBase64String转换为字节数字byte[]
2. MemoryStream初始化字节数组为内存流（使用using自释放内存）
3. 使用XamlReader.Load把（Xaml输入的数据）内存流转换为Section根元素。
4. 把Section元素的内容构造为TextRange元素。
5. 返回TextRang包含的文本Text.

public class AnnotationDataConverter : IValueConverter
{public object Convert(object value, Type targetType, object parameter, CultureInfo culture){// Convert 64 bit binary data into an 8 bit byte array and load// it into a memory buffervar data = System.Convert.FromBase64String(value as string);using (var buffer = new MemoryStream(data)){// Convert memory buffer to object and return textvar section = (Section) XamlReader.Load(buffer);var range = new TextRange(section.ContentStart, section.ContentEnd);return range.Text;}}public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) => null;
}

主窗口内容需要一些私有字段协助运行：

private IAnchorInfo _info;//提供批注的锚定信息类
private AnnotationService _service;//批注服务类
private AnnotationStore _store;//批注存储区
private Stream _stream;

4、运行流程：
主窗口初始化时设置好批注存储导入及绑定到ListBox显示

1. AnnotationService.Enable（AnnotationStory)
2. 绑定批注存储的内容到ListBox

private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{// Load annotations store_stream = new FileStream("storage.xml", FileMode.OpenOrCreate);_service = new AnnotationService(flowDocumentReader);_store = new XmlStreamStore(_stream) {AutoFlush = true};_service.Enable(_store);// Detect when annotations are added or deleted_service.Store.StoreContentChanged +=AnnotationStore_StoreContentChanged;// Bind to annotations in storeBindToAnnotations(_store.GetAnnotations());
}

批注内容变动，触发事件，需重新绑定批注内容到ListBox更新显示

private void AnnotationStore_StoreContentChanged(object sender, StoreContentChangedEventArgs e)
{// Bind to refreshed annotations storeBindToAnnotations(_store.GetAnnotations());
}

批注绑定方法代码：

1. ListBox数据上下文赋值为批注集
2. 使用批注的创建时间属性CreationTime作为降序，构造排序描述类SortDescription
3. 获取ListBox的集合视图ICollectionSource
4. 集合视图的排序集合添加上述的排序描述实例

private void BindToAnnotations(IList<Annotation> annotations)
{// Bind to annotations in storeannotationsListBox.DataContext = annotations;// Sort annotations by creation timevar sortDescription = new SortDescription{PropertyName = "CreationTime",Direction = ListSortDirection.Descending};var view = CollectionViewSource.GetDefaultView(annotationsListBox.DataContext);view.SortDescriptions.Clear();view.SortDescriptions.Add(sortDescription);}

批注选择时定位显示批注锚定位置：

1. 选择项转换为批注类Annotation,并在AnnotationHelper下获取批注信息
2. 获取批注实例的锚定对象TextAnchor
3. 获取锚定对象的文本定位位置点TextPointer
4. 把锚定点当前位置段落Paragraph.BringIntoView滚动到显示出

private void annotationsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{var comment = (sender as ListBox).SelectedItem as Annotation;if (comment != null){// IAnchorInfo info;// service is an AnnotationService object// comment is an Annotation object_info = AnnotationHelper.GetAnchorInfo(_service, comment);var resolvedAnchor = _info.ResolvedAnchor as TextAnchor;var textPointer = (TextPointer) resolvedAnchor.BoundingStart;textPointer.Paragraph.BringIntoView();}
}

最后主窗口关闭时处理批注服务类的关闭：

private void MainWindow_Closed(object sender, EventArgs e)
{if (_service != null && _service.IsEnabled){_service.Disable();_stream.Close();}
}