c# - 如何在 WPF 中的 FlowDocument 中添加页脚？

Question

我的应用程序中有一个FlowDocument如下所示：

   <FlowDocumentScrollViewer Grid.Row="1">
        <FlowDocument>
              <Section>
                    <Paragraph>Header</Paragraph>
               </Section>

               <Section>
                  <Paragraph >
                        Footer
                   </Paragraph>
               </Section>
        </FlowDocument>
   </FlowDocumentScrollViewer>

我想要的是将第一个设置<Section>为文档顶部作为页眉，第二个设置为文档底部作为页脚。

谁能告诉我最好的方法来做到这一点？

score 4 · Accepted Answer

起点是一篇博客文章，它展示了如何包装 aDocumentPaginator并为页面添加装饰。限制是它旨在直接与打印 API 一起使用。它不能直接与查看器一起使用，因为它们要求他们的文档是FlowDocument，并且不可能DocumentPaginator在子类中覆盖。

我找到的解决方案FlowDocumentPageViewer有几个部分。我没有尝试将其调整为FlowDocumentScrollViewer，但使用相同的原则可能是可能的。

自定义 XAML 模板

我首先使用 Blend 为FlowDocumentPageViewer. 我实际上还是想删除一些位，但是页眉/页脚的关键更改是（作为统一差异）

-    <Style TargetType="{x:Type FlowDocumentPageViewer}">
+    <Style TargetType="{x:Type local:CustomFlowDocumentPageViewer}">

                         <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" Uid="Border_47" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                             <AdornerDecorator ClipToBounds="True" Uid="AdornerDecorator_1">
-                                <DocumentPageView DocumentPaginator="{x:Null}" KeyboardNavigation.IsTabStop="False" DocumentViewerBase.IsMasterPage="True" PageNumber="0" KeyboardNavigation.TabIndex="1" KeyboardNavigation.TabNavigation="Local" Uid="DocumentPageView_1"/>
+                                <DocumentPageView DocumentPaginator="{x:Null}" KeyboardNavigation.IsTabStop="False" DocumentViewerBase.IsMasterPage="True" PageNumber="0" KeyboardNavigation.TabIndex="1" KeyboardNavigation.TabNavigation="Local" Uid="DocumentPageView_1" x:Name="DocumentPageView_1"/>
                             </AdornerDecorator>
                         </Border>

子类查看器

由于您应该能够从 XAML 差异中解决问题，因此我的子类称为CustomFlowDocumentPageViewer. 由于FlowDocumentPageViewer要求它Document是 a FlowDocument，因此尝试更改文档是没有意义的。但我能做的是拦截它并将其包装DocumentPaginator在一个自定义的中，我将其注入到DocumentPageView. XAML diff 的后半部分是为了让我能够找到它。

        private DocumentPageView _PageView;

        public DocumentPaginator CustomDocumentPaginator { get; private set; }

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            _PageView = (DocumentPageView)GetTemplateChild("DocumentPageView_1");
            if (_PageView != null) _PageView.DocumentPaginator = CustomDocumentPaginator;
        }

        protected override void OnDocumentChanged()
        {
            base.OnDocumentChanged();

            var doc = Document as FlowDocument;
            CustomDocumentPaginator = doc == null ? null : new DocumentPaginatorWrapper((doc as IDocumentPaginatorSource).DocumentPaginator, new Thickness { Bottom = 32 /* 0.333in */ });
            if (_PageView != null) _PageView.DocumentPaginator = CustomDocumentPaginator;
        }

当然，仅更改有一个大问题DocumentPageView.DocumentPaginator：如果您调用myCustomFlowDocumentPageViewer.Print()，那么它将打印原始文档，没有页眉和页脚。解决方案简单但冗长（大约 100 行）；如果您使用referencesource.microsoft.com，您应该能够弄清楚如何覆盖OnPrintCommand以发送CustomDocumentPaginator到XpsDocumentWriter而不是((IDocumentPaginatorSource)document).DocumentPaginator.

包装文档分页器

我说起点是一篇博客文章，它展示了如何包装一个DocumentPaginator. 它没有提到一些微妙之处，可能是因为它旨在打印一次文档，因此作者没有遇到它们。

DocumentPage是一次性的。当您从包装的分页器中获取页面时，您有责任处理它。如果您不这样做，您可能会发现当您来回导航ArgumentException: Specified Visual is already a child of another Visual or the root of a CompositionTarget时，将包装的页面添加Visual到您的ContainerVisual.
另一种方法ArgumentException是在您已经拥有页面的包装副本时尝试包装页面。例如，如果您打印，就会发生这种情况，因为这XpsDocumentWriter将请求当前正在呈现到屏幕的页面的副本。

因此，您需要仔细管理页面的生命周期。我修改后的分页器包装器版本是

    class DocumentPaginatorWrapper : DocumentPaginator
    {
        private Thickness _Margin;
        private DocumentPaginator _Paginator;

        // Required to avoid "ArgumentException: Specified Visual is already a child of another Visual or the root of a CompositionTarget" when printing
        private IDictionary<int, DocumentPage> _PageCache = new Dictionary<int, DocumentPage>();

        public DocumentPaginatorWrapper(DocumentPaginator paginator, Thickness margin)
        {
            _Margin = margin;
            _Paginator = paginator;
            this.PageSize = paginator.PageSize;

            // Events
            paginator.ComputePageCountCompleted += (s, ev) => this.OnComputePageCountCompleted(ev);
            paginator.GetPageCompleted += (s, ev) => this.OnGetPageCompleted(ev);
            paginator.PagesChanged += (s, ev) => this.OnPagesChanged(ev);
        }

        public override DocumentPage GetPage(int pageNumber)
        {
            DocumentPage cachedPage;
            if (_PageCache.TryGetValue(pageNumber, out cachedPage) && cachedPage.Visual != null) return cachedPage;

            DocumentPage page = _Paginator.GetPage(pageNumber);

            // Create a wrapper visual for transformation and add extras
            ContainerVisual newpage = new ContainerVisual();

            // TODO Transform the wrapped page, add your headers and footers.
            // This is highly idiosyncratic.
            ...

            // NB We assume that page.BleedBox has X=0, Y=0, Size=page.PageSize
            cachedPage = new DocumentPageWrapper(page, newpage, PageSize, new Rect(PageSize), new Rect(page.ContentBox.X, page.ContentBox.Y, page.ContentBox.Width + _Margin.Left + _Margin.Right, page.ContentBox.Height + _Margin.Top + _Margin.Bottom));
            _PageCache[pageNumber] = cachedPage;
            return cachedPage;
        }

        public override bool IsPageCountValid { get { return _Paginator.IsPageCountValid; } }

        public override int PageCount { get { return _Paginator.PageCount; } }

        public override Size PageSize
        {
            get { var value = _Paginator.PageSize; return new Size(value.Width + _Margin.Left + _Margin.Right, value.Height + _Margin.Top + _Margin.Bottom); }
            set { _Paginator.PageSize = new Size(value.Width - _Margin.Left - _Margin.Right, value.Height - _Margin.Top - _Margin.Bottom); }
        }

        public override IDocumentPaginatorSource Source { get { return _Paginator.Source; } }
    }

    /// <summary>
    /// It's necessary to dispose the page returned by the wrapped DocumentPaginator when the page we return is disposed,
    /// because otherwise we inconsistently get ArgumentExceptions due to the page.Visual still being in use.
    /// </summary>
    class DocumentPageWrapper : DocumentPage
    {
        internal DocumentPageWrapper(DocumentPage originalPage, Visual visual, Size pageSize, Rect bleedBox, Rect contentBox)
            : base(visual, pageSize, bleedBox, contentBox)
        {
            _OriginalPage = originalPage;
        }

        private DocumentPage _OriginalPage;

        public override void Dispose()
        {
            base.Dispose();

            if (_OriginalPage != null)
            {
                _OriginalPage.Dispose();
                _OriginalPage = null;
            }
        }
    }

score -1 · Accepted Answer

你可以试试这个..希望这有帮助..

<Section Name="MainBody" SectionExtensions.ResetPageNumbers="True">
    <!-- Add the document title to the header -->
    <SectionExtensions.HeaderTemplate>
        <DataTemplate>
            <Border BorderBrush="Black" BorderThickness="0,0,0,1">
                <TextBlock Text="Document title" FontSize="16" />
            </Border>
        </DataTemplate>
    </SectionExtensions.HeaderTemplate>


    <!-- Add the page count to the footer -->
    <SectionExtensions.FooterTemplate>
        <DataTemplate>
            <Border BorderBrush="Black" BorderThickness="0,1,0,0">
                <TextBlock Text="{Binding}" FontSize="16" />
            </Border>
        </DataTemplate>
    </SectionExtensions.FooterTemplate>
    <Paragraph>
    ...
    </Paragraph>
</Section>

c# - 如何在 WPF 中的 FlowDocument 中添加页脚？

2 回答 2

自定义 XAML 模板

子类查看器

包装文档分页器

Related

Reference