如何在 WPF 中向流文档添加页脚
本文关键字：文档 添加 WPF | 更新日期: 2023-09-27 18:17:04
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<Section>设置为保留在文档顶部作为页眉，将第二个设置为保留在文档底部作为页脚。
谁能告诉我最好的方法？
起点是一篇博客文章，展示了如何包装DocumentPaginator并向页面添加装饰。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，因为他们要求他们的文档是FlowDocument的，并且不可能覆盖子类中的DocumentPaginator。
我为FlowDocumentPageViewer找到的解决方案有几个部分。我没有尝试将其改编为FlowDocumentScrollViewer，但使用相同的原理是可能的。
自定义 XAML 模板
我首先使用 Blend 提取 FlowDocumentPageViewer 的默认 XAML 模板。无论如何，我实际上想删除一些位，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>
对查看器进行子类化
由于您应该能够从 XAML 差异中找出问题，因此我的子类称为 CustomFlowDocumentPageViewer 。由于FlowDocumentPageViewer要求其Document是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DocumentPaginator包装在一个自定义的中，我将其注入DocumentPageView. XAML 差异的后半部分是使我能够找到它。
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，只更改DocumentPageView.DocumentPaginator有一个大问题：如果您调用myCustomFlowDocumentPageViewer.Print()，那么它将打印原始文档，没有页眉和页脚。解决方案简单但很长(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以将CustomDocumentPaginator发送到XpsDocumentWriter而不是((IDocumentPaginatorSource)document).DocumentPaginator。
换行文档分页器
我说起点是一篇博客文章，展示了如何包装DocumentPaginator。有一些微妙之处没有提到，可能是因为它打算打印一次文档，所以作者没有遇到它们。
-
DocumentPage是一次性的。当您从包装的分页器获取页面时，您有责任处理它。如果不这样做，您可能会发现，当您来回导航时，将包装页面的Visual添加到ContainerVisual时会随机ArgumentException: Specified Visual is already a child of another Visual or the root of a CompositionTarget。 - 获得该
ArgumentException的另一种方法是，当您已经有页面的包装副本时，尝试包装页面。 例如，如果您打印，可能会发生这种情况，因为XpsDocumentWriter将请求当前正在呈现到屏幕上的页面的副本。
因此，您需要仔细管理页面的生命周期。我的分页器包装器的修改版本是
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;
}
}
}
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>