jbt*_*ule 10 c# wpf xaml .net-4.0 flowdocument
我正在寻找一种干净的通用方法的概念来描述XAML FlowDocument中重复的页眉和页脚,而不需要任何代码.它只需要在从C#渲染到XPS时正确显示.
Dav*_*ler 10
几个月前我遇到了同样的问题,发现这些链接非常有用: WPF多页面报告第四部分分页 http://www.codeproject.com/KB/WPF/PimpedDocumentPaginator.aspx
我使用的基本技术是通过DynamicDocumentPaginator如下派生来创建自定义分页器:
internal class HeaderFooterPaginator<THeaderModel, TFooterModel> : DynamicDocumentPaginator where THeaderModel : PageNumberModel, new() where TFooterModel : PageNumberModel, new()
{
...
}
在我的情况下,THeaderFooterModel并且TFooterModel是PageNumberModel类型的子类,因为我需要页眉或页脚才能显示当前页码.
public class PageNumberModel
{
public int PageNumber { get; set; }
}
自定义分页器委托原始XPS分页器完成大部分工作,因此它将它存储在构造函数中.
该THeaderModel和TFooterModel类型允许分页程序来检索XAML DataTemplates为每种类型的,这是允许你指定在XAML页眉和页脚的布局,而不诉诸自定义绘制代码.
在我的代码中,页眉和页脚是固定大小的,因此在创建分页器时,它会检索页眉和页脚模板以确定要保留多少空间.
在提供的链接中的示例代码中,他们用于为页眉和页脚保留空间的技术是使用缩放变换来缩小原始内容.相反,我告诉原始分页器使用缩小的页面大小,然后将原始分页器生成的页面添加到a ContainerVisual并设置它Offset.如果页眉和页脚的大小是动态的,则可能无法执行此操作,因为页数会不断变化.
我记得的另一个复杂问题是,Dispatcher在添加页眉和页脚时需要使用队列(见AddHeaderOrFooterToContainerAsync下文).否则数据绑定不起作用.我们稍微颠覆了WPF渲染模型以使其工作.
如果不包含代码,这将很难解释,所以我在下面附加了自定义渲染器代码.我已经删除了一些不相关的东西,所以如果它不能编译,那可能是原因:-)
请注意,传递页码偏移量是因为我们的XPS文档由多个FlowDocument部分组成,并且调用代码会跟踪当前的总页码.
希望这可以帮助!
internal class HeaderFooterPaginator<THeaderModel, TFooterModel> : DynamicDocumentPaginator where THeaderModel : PageNumberModel, new() where TFooterModel : PageNumberModel, new()
{
private readonly double _footerHeight;
private readonly DataTemplate _footerTemplate;
private readonly double _headerHeight;
private readonly DataTemplate _headerTemplate;
private Size _newPageSize;
private Size _originalPageSize;
private readonly DynamicDocumentPaginator _originalPaginator;
private readonly int _pageNumberOffset;
private readonly FlowDocument _paginatorSource;
private const double HeaderAndFooterMarginHeight = 5;
private const double HeaderAndFooterMarginWidth = 10;
public HeaderFooterPaginator(int pageNumberOffset, FlowDocument document)
{
if (document == null)
{
throw new ArgumentNullException("document");
}
_paginatorSource = document;
if (_paginatorSource == null)
{
throw new InvalidOperationException("Could not create a clone of the document being paginated.");
}
_originalPaginator = ((IDocumentPaginatorSource) _paginatorSource).DocumentPaginator as DynamicDocumentPaginator;
if (_originalPaginator == null)
{
throw new InvalidOperationException("The paginator must be a DynamicDocumentPaginator.");
}
_headerTemplate = GetModelDataTemplate(typeof (THeaderModel));
_footerTemplate = GetModelDataTemplate(typeof (TFooterModel));
var headerSize = GetModelContentSize(new THeaderModel { PageNumber = int.MaxValue }, _headerTemplate, _originalPaginator.PageSize);
var footerSize = GetModelContentSize(new TFooterModel { PageNumber = int.MaxValue }, _footerTemplate, _originalPaginator.PageSize);
_headerHeight = double.IsInfinity(headerSize.Height) ? 0 : headerSize.Height;
_footerHeight = double.IsInfinity(footerSize.Height) ? 0 : footerSize.Height;
_pageNumberOffset = pageNumberOffset;
SetPageSize(new Size(document.PageWidth, document.PageHeight));
}
private void AddHeaderOrFooterToContainerAsync<THeaderOrFooter>(ContainerVisual container, double areaWidth, double areaHeight, Vector areaOffset, FrameworkTemplate template, int displayPageNumber) where THeaderOrFooter : PageNumberModel, new()
{
if (template == null)
{
return;
}
var visual = GetModelContent(new THeaderOrFooter { PageNumber = displayPageNumber }, template);
if (visual != null)
{
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, new Action(() =>
{
visual.Measure(_originalPageSize);
visual.Arrange(new Rect(0, 0, areaWidth, areaHeight));
visual.UpdateLayout();
var headerContainer = new ContainerVisual { Offset = areaOffset };
headerContainer.Children.Add(visual);
container.Children.Add(headerContainer);
}));
}
}
public override void ComputePageCount()
{
_originalPaginator.ComputePageCount();
}
private static void FlushDispatcher()
{
Dispatcher.CurrentDispatcher.Invoke(DispatcherPriority.ApplicationIdle, new DispatcherOperationCallback(delegate { return null; }), null);
}
private static FrameworkElement GetModelContent(object dataModel, FrameworkTemplate modelTemplate)
{
if (modelTemplate == null)
{
return null;
}
var content = modelTemplate.LoadContent() as FrameworkElement;
if (content == null)
{
return null;
}
content.DataContext = dataModel;
return content;
}
private static Size GetModelContentSize(object dataModel, FrameworkTemplate modelTemplate, Size availableSize)
{
var content = GetModelContent(dataModel, modelTemplate);
if (content == null)
{
return Size.Empty;
}
FlushDispatcher();
content.Measure(availableSize);
return content.DesiredSize;
}
private DataTemplate GetModelDataTemplate(Type modelType)
{
var key = new DataTemplateKey(modelType);
return _paginatorSource.TryFindResource(key) as DataTemplate;
}
public override ContentPosition GetObjectPosition(object value)
{
return _originalPaginator.GetObjectPosition(value);
}
public override DocumentPage GetPage(int pageNumber)
{
if (!_originalPaginator.IsPageCountValid)
{
ComputePageCount();
}
var originalPage = _originalPaginator.GetPage(pageNumber);
var newPage = new ContainerVisual();
var displayPageNumber = _pageNumberOffset + pageNumber;
var internalWidth = _originalPageSize.Width - 2*HeaderAndFooterMarginWidth;
AddHeaderOrFooterToContainerAsync<THeaderModel>(newPage, internalWidth, _headerHeight, new Vector(HeaderAndFooterMarginWidth, HeaderAndFooterMarginHeight), _headerTemplate, displayPageNumber);
var smallerPage = new ContainerVisual();
smallerPage.Children.Add(originalPage.Visual);
smallerPage.Offset = new Vector(HeaderAndFooterMarginWidth, HeaderAndFooterMarginHeight + _headerHeight);
newPage.Children.Add(smallerPage);
AddHeaderOrFooterToContainerAsync<TFooterModel>(newPage, internalWidth, _footerHeight, new Vector(HeaderAndFooterMarginWidth, _originalPageSize.Height - HeaderAndFooterMarginHeight - _footerHeight), _footerTemplate, displayPageNumber);
return new DocumentPage(newPage, _originalPageSize, originalPage.BleedBox, originalPage.ContentBox);
}
public override int GetPageNumber(ContentPosition contentPosition)
{
return _originalPaginator.GetPageNumber(contentPosition);
}
public override ContentPosition GetPagePosition(DocumentPage page)
{
return _originalPaginator.GetPagePosition(page);
}
private void SetPageSize(Size pageSize)
{
_originalPageSize = pageSize;
// Decrease the available page size by the height of the header and footer. The page is offset by the header height later on.
var sizeRect = new Rect(pageSize);
sizeRect.Inflate(-HeaderAndFooterMarginWidth, -(HeaderAndFooterMarginHeight + _footerHeight/2 + _headerHeight/2));
_originalPaginator.PageSize = _newPageSize = sizeRect.Size;
// Change page size of the document to the size of the content area
_paginatorSource.PageHeight = _newPageSize.Height;
_paginatorSource.PageWidth = _newPageSize.Width;
}
public override bool IsPageCountValid
{
get { return _originalPaginator.IsPageCountValid; }
}
public override int PageCount
{
get { return _originalPaginator.PageCount; }
}
public override Size PageSize
{
get { return _newPageSize; }
set { SetPageSize(value); }
}
public override IDocumentPaginatorSource Source
{
get { return _originalPaginator.Source; }
}
}