文档 doc.Add(pdf) 可能吗？

Question

我正在尝试将 pdf 添加到另一个 pdf。文档 doc.Add(IElement) 是我知道要做的事情，但我在添加 pdf 时遇到问题。我尝试添加图像并且成功了。如何将 pdf 文件添加到我的文档中？

iTextSharp.text.Image img;
foreach (var buf in List) {
   myDoc.NewPage();
   img = iTextSharp.text.Image.GetInstance(buf);
   img.ScaleToFit(612f, 792f);
   img.Alignment = iTextSharp.text.Image.ALIGN_CENTER | iTextSharp.text.Image.ALIGN_MIDDLE;
   myDoc.Add(img);
}

Answer 1

您不能使用 Document.Add() 但它仍然非常简单。首先，您需要创建一个 PdfReader 对象来读取源文档。然后使用目标文档的 PdfWriter 并在要导入的每个页面上调用其 GetImportedPage(reader, pageNumber) 方法。这将为您提供一个 PdfImportedPage 对象，您可以将其传递给 PdfWriter.DirectContent.AddTemplate()。

下面是一个针对 iTextSharp 5.1.1.0 的完整工作 C# 2010 WinForms 应用程序，展示了所有这些步骤。首先，它创建一个示例文件 (File1)，然后创建第二个文件 (File2) 并向其中添加第一个文件。它还做了一些额外的事情，以展示一些边缘情况，特别是如何处理旋转页面。具体细节请参见代码注释。

using System;
using System.Text;
using System.Windows.Forms;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //The names of the two files that we'll create
            string File1 = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "File1.pdf");
            string File2 = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "File2.pdf");

            //Create a test file to merge into the second file
            using (FileStream fs = new FileStream(File1, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                //We'll create this one landscape to show some checks that need to be done later
                using (Document doc = new Document(PageSize.TABLOID.Rotate()))
                {
                    using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
                    {
                        doc.Open();
                        doc.Add(new Paragraph("File 1"));
                        doc.Close();
                    }
                }
            }

            //Create our second file
            using (FileStream fs = new FileStream(File2, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                //Create this one as a regular US Letter portrait sized document
                using (Document doc = new Document(PageSize.LETTER))
                {
                    using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
                    {
                        doc.Open();

                        doc.Add(new Paragraph("File 2"));

                        //Create a PdfReader to read our first file
                        PdfReader r = new PdfReader(File1);

                        //Store the number of pages
                        int pageCount = r.NumberOfPages;

                        //Variables which will be set in the loop below
                        iTextSharp.text.Rectangle rect;
                        PdfImportedPage imp;

                        //Loop through each page in the source document, remember that page indexes start a one and not zero
                        for (int i = 1; i <= pageCount; i++)
                        {
                            //Get the page's dimension and rotation
                            rect = r.GetPageSizeWithRotation(i);

                            //Get the actual page
                            imp = writer.GetImportedPage(r, i);

                            //These two commands must happen in this order
                            //First change the "default page size" to match the current page's size
                            doc.SetPageSize(rect);
                            //then add a new blank page which we'll fill with our actual page
                            doc.NewPage();

                            //If the document has been rotated one twist left or right (90 degrees) then we need to add it a little differently
                            if (rect.Rotation == 90 || rect.Rotation == 270)
                            {
                                //Add the page accounting for the rotation
                                writer.DirectContent.AddTemplate(imp, 0, -1, 1, 0, 0, rect.Height);
                            }
                            else
                            {
                                //Add the page normally
                                writer.DirectContent.AddTemplate(imp, 0, 0);
                            }

                        }

                        doc.Close();
                    }
                }
            }
            this.Close();
        }
    }
}