使用iTextsharp从现有的PDF中删除元数据

Question

我创建了一个pdf并在其中添加了一个元数据，并且还使用iTextsharp库对其进行了加密。 现在我想从pdf中删除加密。我成功地使用了iTextSharp，但无法删除我添加的元数据。 任何人都可以请giude我如何删除元数据。这很紧急。

谢谢。

Answer 1

当删除元数据时，最容易直接使用PdfReader对象。一旦你这样做，你可以写回到磁盘。下面的代码是针对iTextSharp 5.1.2.0的完整工作的C＃2010 WinForms应用程序。它首先使用某些元数据创建PDF，然后使用PdfReader修改PDF的内存版本，最后将更改写入磁盘。请参阅代码以获取其他意见。

using System; 
using System.Collections.Generic; 
using System.IO; 
using System.Windows.Forms; 
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) { 
      //File with meta data added 
      string InputFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Test.pdf"); 
      //File with meta data removed 
      string OutputFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "Output.pdf"); 

      //Create a file with meta data, nothing special here 
      using (FileStream FS = new FileStream(InputFile, FileMode.Create, FileAccess.Write, FileShare.None)) { 
       using (Document Doc = new Document(PageSize.LETTER)) { 
        using (PdfWriter writer = PdfWriter.GetInstance(Doc, FS)) { 
         Doc.Open(); 
         Doc.Add(new Paragraph("Test")); 
         //Add a standard header 
         Doc.AddTitle("This is a test"); 
         //Add a custom header 
         Doc.AddHeader("Test Header", "This is also a test"); 
         Doc.Close(); 
        } 
       } 
      } 

      //Read our newly created file 
      PdfReader R = new PdfReader(InputFile); 
      //Loop through each piece of meta data and remove it 
      foreach (KeyValuePair<string, string> KV in R.Info) { 
       R.Info.Remove(KV.Key); 
      } 

      //The code above modifies an in-memory representation of the PDF, we need to write these changes to disk now 
      using (FileStream FS = new FileStream(OutputFile, FileMode.Create, FileAccess.Write, FileShare.None)) { 
       using (Document Doc = new Document()) { 
        //Use the PdfCopy object to copy each page 
        using (PdfCopy writer = new PdfCopy(Doc, FS)) { 
         Doc.Open(); 
         //Loop through each page 
         for (int i = 1; i <= R.NumberOfPages; i++) { 
          //Add it to the new document 
          writer.AddPage(writer.GetImportedPage(R, i)); 
         } 
         Doc.Close(); 
        } 
       } 
      } 

      this.Close(); 
     } 
    } 
}