使用iTextSharp创建PDF时输入页码

Question

我正在使用ASP MVC，我使用iTextSharp在我的应用程序中生成PDF。但现在我有一个问题：我打印列表，当存在多个页面时，我想显示页码（例如：Page 1 to 4）。我找到了一些例子，但我认为它比我需要做的更复杂（比如exameple）。

修改 我找到了example 2。我可以计算页数，但我不能在页面中打印数字。

我做了什么：

public ActionResult downloadListaISCC(DateTime? DataFimFiltro)
{

//Code to generate list to PDF

   //My document
   Document doc1 = new Document();
   doc1.SetPageSize(iTextSharp.text.PageSize.A4);
   doc1.SetMargins(0f, 0f, 0f, 0f);
   doc1.NewPage();

   MemoryStream pdfStream = new MemoryStream();
   PdfWriter pdfWriter = PdfWriter.GetInstance(doc1, pdfStream);

   //Code to create table
   doc1.Add(table); //table list in document

   //Follow the example 2 (link)
   pdfWriter.CloseStream = true;
   doc1.Close();


   //E fui seguindo o exemplo do segundo link
   string file = "D:/gerarPDFOleotorres/"+ nomeDoc +""; 

   // add page numbers
   Document copyDoc = new Document();
   PdfCopy copyPdf = new PdfCopy(copyDoc, new FileStream(file, FileMode.Create));
   copyPdf.SetPageSize(PageSize.A4.Rotate());
   copyDoc.Open();

   // read the initial pdf document
   PdfReader reader = new PdfReader(pdfStream.ToArray());
   int totalPages = reader.NumberOfPages;

   PdfImportedPage copiedPage = null;
   iTextSharp.text.pdf.PdfCopy.PageStamp stamper = null;

   for (int i = 0; i < totalPages; i++)
   {

       // get the page and create a stamper for that page
       copiedPage = copyPdf.GetImportedPage(reader, (i + 1));
       stamper = copyPdf.CreatePageStamp(copiedPage);

       // add a page number to the page
       ColumnText.ShowTextAligned(stamper.GetUnderContent(), Element.ALIGN_CENTER, new Phrase((i + 1) + "/" + totalPages, fontetexto), 820f, 15, 0);
        stamper.AlterContents();

       // add the altered page to the new document
       copyPdf.AddPage(copiedPage);
   }

   copyDoc.Close();
   reader.Close();

   // flush and clear the document from memory
   pdfStream.Flush();
   pdfStream.Close();
    }

Answer 1

基本上，您有两种选择：要么一次创建文档，要么两次创建文档。

如果您一次创建文档，您事先不知道Y的值（总页数），因此您需要创建一个PdfTemplate对象作为占位符。这在MovieCountries1示例中进行了演示。

在此示例中，我们创建了一个扩展TableHeader的{​​{1}}类。我们在PdfPageEventHelper方法中为PdfTemplate创建total类的实例，我们在OnOpenDocument()方法中使用此total占位符，我们在其中添加标题或页脚，我们用OnEndPage()方法填写总页数。

这种方法的缺点是很难预测OnCloseDocument()所需的尺寸。优点是您可以一次创建文档（您不需要先在内存中创建文档）。

如果您通过两次传递创建文档，则首先创建没有页眉/页脚的文档，然后检查文档以查找它包含的页数。然后使用total将页码添加到每个页面。这显示在TwoPasses示例中。

这些例子来自我的书“iText in Action - Second Edition”。您可以从以下网址免费下载第6章：http://manning.com/lowagie2/samplechapter6.pdf

如果您对特定功能有疑问，请参阅[官方文档] [4]。

更新：我不明白为什么你更喜欢看非官方的例子。我给你的例子如下：

PdfStamper

但是出于某种原因，你用谷歌搜索了一个更复杂的例子（并且你需要的东西太过分了）。

只需将using (PdfStamper stamper = new PdfStamper(reader, ms2)) { // Loop over the pages and add a header to each page int n = reader.NumberOfPages; for (int i = 1; i <= n; i++) { // Add content } } 部分替换为：

// Add content

请注意，我在ColumnText.ShowTextAligned(stamper.GetUnderContent(), Element.ALIGN_CENTER, new Phrase((i + 1) + "/" + totalPages, fontetexto), 297f, 15f, 0); 方法中调整了x值。您正在创建一个A4大小的页面，这意味着您的页面宽度为595个用户单位。如果在位置x = 820处添加页码，则会添加页脚，但它将位于页面的可见区域之外。如果不知道每种方法的参数，请不要复制/粘贴代码。

Answer 2

对于记录 - 我用这种方式

byte[] bytes = memoryStream.ToArray();

                //Save pdf in the temporary location.
System.IO.File.WriteAllBytes(Server.MapPath("~/TempReports/") + lbReports.Text + "_JEA.pdf", bytes);

/*This is a page counter - it stamps the number of pages in the document. 
 It will read dynamically the 'document' that was just closed above [document.Close();] from the location, 
 then in memory will write the new content plus the one from [byte[] bytes = memoryStream.ToArray();] 
 Solution has been applied from: https://www.aspsnippets.com/Articles/iTextSharp-Add-Page-numbers-to-existing-PDF-using-C-and-VBNet.aspx
 */
try
{
    File.ReadAllBytes(Server.MapPath("~/TempReports/") + lbReports.Text + "_JEA.pdf");
    iTextSharp.text.Font blackFont = FontFactory.GetFont("Arial", 7, iTextSharp.text.Font.BOLD, BaseColor.BLACK);
    using (MemoryStream stream = new MemoryStream())
    {
        PdfReader reader = new PdfReader(bytes);
        using (PdfStamper stamper = new PdfStamper(reader, stream))
        {
            int pages = reader.NumberOfPages;
            for (int i = 1; i <= pages; i++)
            {
                ColumnText.ShowTextAligned(stamper.GetUnderContent(i),
                 @Element.ALIGN_LEFT, new Phrase(lbReports.Text + " - HD - JEA", blackFont), 63f, 24f, 0);

                ColumnText.ShowTextAligned(stamper.GetUnderContent(i),
                @Element.ALIGN_CENTER, new Phrase("Page " + i.ToString() + " of " + pages, blackFont), 300f, 24f, 0);

                ColumnText.ShowTextAligned(stamper.GetUnderContent(i),
                @Element.ALIGN_RIGHT, new Phrase("" + DateTime.Now, blackFont), 549f, 24f, 0);
            }

            txConnection.Text = "This report contains " + pages + " page(s)";
        }

        bytes = stream.ToArray();

    }//End of page counter

    /*System.IO.File.WriteAllBytes will write all bytes to file again*/

    System.IO.File.WriteAllBytes(Server.MapPath("~/TempReports/") + lbReports.Text + "_JEA.pdf", bytes);

    // Temporary path that is used to display the pdf in the embed.
    System.IO.File.WriteAllBytes(Server.MapPath("~/TempReports/ReportsEmbed/") + lbReports.Text + "_JEA.pdf", bytes);

    /*this is what sends the PDF to the embed viewer object
     The ltEmbed is what receives the plugin to dispplay the file*/

    string embed = "<object data=\"{0}\" type=\"application/pdf\" width=\"698px\" height=\"450px\">";
    embed += "If you are unable to view file, you can download it from <a href = \"{0}\">here</a>";
    embed += " or download <a target = \"_blank\" href = \"http://get.adobe.com/reader/\">Adobe PDF Reader</a> to view it.";
    embed += "</object>";

    ltEmbed.Text = string.Format(embed, ("http://localhost:65423/TempReports/ReportsEmbed/") + lbReports.Text + "_JEA.pdf");
    memoryStream.Close();

    this.Context.ApplicationInstance.CompleteRequest();
}
catch (DocumentException exe)
{
    txConnection.Text = "There has been an error generating the file. Please try again. Error: " + exe;
}