Asp.net “开始”页面仅生成第一页的页眉

我有以下web开发代码：

protected internal class MyEventHandler : iText.Kernel.Events.IEventHandler
{
    public virtual void HandleEvent(iText.Kernel.Events.Event @event)
    {
        iText.Kernel.Events.PdfDocumentEvent docEvent = 
                (iText.Kernel.Events.PdfDocumentEvent)@event;
        PdfDocument pdfDoc = docEvent.GetDocument();
    }

    public void onStartPage(
        iText.Kernel.Pdf.PdfWriter writer, iText.Layout.Document document)
    {
        // paragragrap for start pages
        …
    }
}

以及其他为页面添加更多内容的代码。

---

它只生成第一页的标题。

您混合了来自不同iText版本的事件处理

在iText 5中，您通常通过扩展

PdfPageEventHelper

来实现

IPdfPageEvent

，在这里您有单独的方法，如

void OnStartPage(PdfWriter writer, Document document)
void OnEndPage(PdfWriter writer, Document document)

等等

在iText 7中，您实现了只有一个方法的

IEventHandler

void HandleEvent(Event @event)

您可以仅为一种事件类型注册事件处理程序，从而在

HandleEvent

中知道正确的事件已到达，或者根据事件类型（

@event.GetEventType（）

）确定获得的事件类型并执行相应的代码

更改页面旋转的事件侦听器示例 例如，在事件处理程序中，仅为页面开始注册

C07E01_EventHandlers.PageRotationEventHandler eventHandler = new PageRotationEventHandler();
pdf.AddEventHandler(PdfDocumentEvent.START_PAGE, eventHandler);

在其事件处理方法中，会相应地进行操作

public virtual void HandleEvent(Event @event) {
    PdfDocumentEvent docEvent = (PdfDocumentEvent)@event;
    docEvent.GetPage().Put(PdfName.Rotate, this.rotation);
}

完整示例类：

public class C07E01_EventHandlers {
    public const String DEST = "../../../results/chapter07/jekyll_hyde_page_orientation.pdf";

    public static readonly PdfNumber PORTRAIT = new PdfNumber(0);

    public static readonly PdfNumber LANDSCAPE = new PdfNumber(90);

    public static readonly PdfNumber INVERTEDPORTRAIT = new PdfNumber(180);

    public static readonly PdfNumber SEASCAPE = new PdfNumber(270);

    public static void Main(String[] args) {
        FileInfo file = new FileInfo(DEST);
        file.Directory.Create();
        new C07E01_EventHandlers().CreatePdf(DEST);
    }

    public virtual void CreatePdf(String dest) {
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));
        pdf.GetCatalog().SetPageLayout(PdfName.TwoColumnLeft);
        C07E01_EventHandlers.PageRotationEventHandler eventHandler = new PageRotationEventHandler();
        pdf.AddEventHandler(PdfDocumentEvent.START_PAGE, eventHandler);
        Document document = new Document(pdf, PageSize.A8);
        document.Add(new Paragraph("Dr. Jekyll"));
        eventHandler.SetRotation(INVERTEDPORTRAIT);
        document.Add(new AreaBreak());
        document.Add(new Paragraph("Mr. Hyde"));
        eventHandler.SetRotation(LANDSCAPE);
        document.Add(new AreaBreak());
        document.Add(new Paragraph("Dr. Jekyll"));
        eventHandler.SetRotation(SEASCAPE);
        document.Add(new AreaBreak());
        document.Add(new Paragraph("Mr. Hyde"));
        document.Close();
    }

    protected internal class PageRotationEventHandler : IEventHandler {
        protected internal PdfNumber rotation = C07E01_EventHandlers.PORTRAIT;

        public virtual void SetRotation(PdfNumber orientation) {
            this.rotation = orientation;
        }

        public virtual void HandleEvent(Event @event) {
            PdfDocumentEvent docEvent = (PdfDocumentEvent)@event;
            docEvent.GetPage().Put(PdfName.Rotate, this.rotation);
        }

        internal PageRotationEventHandler() {
        }
    }
}

添加页眉和页脚的页面侦听器示例 在评论中，您要求提供页眉示例，而不是页面旋转示例。例如，在第3章（）示例中，事件侦听器用于添加背景、水印、页眉和页脚：

public class C03E03_UFO {

    internal static PdfFont helvetica = null;

    internal static PdfFont helveticaBold = null;

    public static void Main(String[] args) {
        helvetica = PdfFontFactory.CreateFont(StandardFonts.HELVETICA);
        helveticaBold = PdfFontFactory.CreateFont(StandardFonts.HELVETICA_BOLD);
        ...
    }

    protected internal virtual void CreatePdf(String dest) {
        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));
        pdf.AddEventHandler(PdfDocumentEvent.END_PAGE, new C03E03_UFO.MyEventHandler(this));
        ...
    }

    ...

    protected internal class MyEventHandler : IEventHandler {
        public virtual void HandleEvent(Event @event) {
            PdfDocumentEvent docEvent = (PdfDocumentEvent)@event;
            PdfDocument pdfDoc = docEvent.GetDocument();
            PdfPage page = docEvent.GetPage();
            int pageNumber = pdfDoc.GetPageNumber(page);
            Rectangle pageSize = page.GetPageSize();
            PdfCanvas pdfCanvas = new PdfCanvas(page.NewContentStreamBefore(), page.GetResources(), pdfDoc);
            //Set background
            Color limeColor = new DeviceCmyk(0.208f, 0, 0.584f, 0);
            Color blueColor = new DeviceCmyk(0.445f, 0.0546f, 0, 0.0667f);
            pdfCanvas.SaveState()
                     .SetFillColor(pageNumber % 2 == 1 ? limeColor : blueColor)
                     .Rectangle(pageSize.GetLeft(), pageSize.GetBottom(), pageSize.GetWidth(), pageSize.GetHeight())
                     .Fill()
                     .RestoreState();
            //Add header and footer
            pdfCanvas.BeginText()
                     .SetFontAndSize(C03E03_UFO.helvetica, 9)
                     .MoveText(pageSize.GetWidth() / 2 - 60, pageSize.GetTop() - 20)
                     .ShowText("THE TRUTH IS OUT THERE")
                     .MoveText(60, -pageSize.GetTop() + 30)
                     .ShowText(pageNumber.ToString())
                     .EndText();
            //Add watermark
            iText.Layout.Canvas canvas = new iText.Layout.Canvas(pdfCanvas, pdfDoc, page.GetPageSize());
            canvas.SetFontColor(ColorConstants.WHITE);
            canvas.SetProperty(Property.FONT_SIZE, UnitValue.CreatePointValue(60));
            canvas.SetProperty(Property.FONT, C03E03_UFO.helveticaBold);
            canvas.ShowTextAligned(new Paragraph("CONFIDENTIAL"), 298, 421, pdfDoc.GetPageNumber(page), TextAlignment.
                CENTER, VerticalAlignment.MIDDLE, 45);
            pdfCanvas.Release();
        }

        internal MyEventHandler(C03E03_UFO _enclosing) {
            this._enclosing = _enclosing;
        }

        private readonly C03E03_UFO _enclosing;
    }
}

---

严格来说，该示例侦听的是

PdfDocumentEvent.END\u PAGE

，而不是

PdfDocumentEvent.START\u PAGE

。不过，这种差异不会造成太大的伤害。

在无状态编程（即asp.net）中，像C07E01\u EventHandlers这样的东西并不存在。请，你能为页眉而不是一页写一个例子吗。Avipublic virtual void HandleEvent（Event@Event）{PdfDocumentEvent docEvent=（PdfDocumentEvent）@Event；docEvent.GetPage（）.Put（PdfName.Rotate，this.rotation）；}如果要添加段落，则此操作无效。请帮忙。

public class C03E03_UFO {

    internal static PdfFont helvetica = null;

    internal static PdfFont helveticaBold = null;

    public static void Main(String[] args) {
        helvetica = PdfFontFactory.CreateFont(StandardFonts.HELVETICA);
        helveticaBold = PdfFontFactory.CreateFont(StandardFonts.HELVETICA_BOLD);
        ...
    }

    protected internal virtual void CreatePdf(String dest) {
        //Initialize PDF document
        PdfDocument pdf = new PdfDocument(new PdfWriter(dest));
        pdf.AddEventHandler(PdfDocumentEvent.END_PAGE, new C03E03_UFO.MyEventHandler(this));
        ...
    }

    ...

    protected internal class MyEventHandler : IEventHandler {
        public virtual void HandleEvent(Event @event) {
            PdfDocumentEvent docEvent = (PdfDocumentEvent)@event;
            PdfDocument pdfDoc = docEvent.GetDocument();
            PdfPage page = docEvent.GetPage();
            int pageNumber = pdfDoc.GetPageNumber(page);
            Rectangle pageSize = page.GetPageSize();
            PdfCanvas pdfCanvas = new PdfCanvas(page.NewContentStreamBefore(), page.GetResources(), pdfDoc);
            //Set background
            Color limeColor = new DeviceCmyk(0.208f, 0, 0.584f, 0);
            Color blueColor = new DeviceCmyk(0.445f, 0.0546f, 0, 0.0667f);
            pdfCanvas.SaveState()
                     .SetFillColor(pageNumber % 2 == 1 ? limeColor : blueColor)
                     .Rectangle(pageSize.GetLeft(), pageSize.GetBottom(), pageSize.GetWidth(), pageSize.GetHeight())
                     .Fill()
                     .RestoreState();
            //Add header and footer
            pdfCanvas.BeginText()
                     .SetFontAndSize(C03E03_UFO.helvetica, 9)
                     .MoveText(pageSize.GetWidth() / 2 - 60, pageSize.GetTop() - 20)
                     .ShowText("THE TRUTH IS OUT THERE")
                     .MoveText(60, -pageSize.GetTop() + 30)
                     .ShowText(pageNumber.ToString())
                     .EndText();
            //Add watermark
            iText.Layout.Canvas canvas = new iText.Layout.Canvas(pdfCanvas, pdfDoc, page.GetPageSize());
            canvas.SetFontColor(ColorConstants.WHITE);
            canvas.SetProperty(Property.FONT_SIZE, UnitValue.CreatePointValue(60));
            canvas.SetProperty(Property.FONT, C03E03_UFO.helveticaBold);
            canvas.ShowTextAligned(new Paragraph("CONFIDENTIAL"), 298, 421, pdfDoc.GetPageNumber(page), TextAlignment.
                CENTER, VerticalAlignment.MIDDLE, 45);
            pdfCanvas.Release();
        }

        internal MyEventHandler(C03E03_UFO _enclosing) {
            this._enclosing = _enclosing;
        }

        private readonly C03E03_UFO _enclosing;
    }
}