如何以编程方式阅读PDF书签

Question

我正在使用PDF转换器访问PDF中的图形数据.一切正常,但我没有得到书签列表.是否有可以读取PDF书签的命令行应用程序或C#组件？我找到了iText和SharpPDF库,我正在浏览它们.你做过这样的事吗？

Answer 1

请尝试以下代码

PdfReader pdfReader = new PdfReader(filename);

IList<Dictionary<string, object>> bookmarks = SimpleBookmark.GetBookmark(pdfReader);

for(int i=0;i<bookmarks.Count;i++)
{
    MessageBox.Show(bookmarks[i].Values.ToArray().GetValue(0).ToString());

    if (bookmarks[i].Count > 3)
    {
        MessageBox.Show(bookmarks[i].ToList().Count.ToString());
    }
}

注意:不要忘记将iTextSharp DLL添加到项目中.

Answer 2

由于书签位于树结构中（https://en.wikipedia.org/wiki/Tree_(data_struct)），因此我在这里使用了一些递归来收集所有书签及其子书签。

iTextSharp 为我解决了这个问题。

dotnet add package iTextSharp

使用以下代码收集所有书签：

using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using iTextSharp.text.pdf;

namespace PdfManipulation
{
    class Program
    {
        static void Main(string[] args)
        {
            StringBuilder bookmarks = ExtractAllBookmarks("myPdfFile.pdf");
        }

        private static StringBuilder ExtractAllBookmarks(string pdf)
        {
            StringBuilder sb = new StringBuilder();
            PdfReader reader = new PdfReader(pdf);
            IList<Dictionary<string, object>> bookmarksTree = SimpleBookmark.GetBookmark(reader);
            foreach (var node in bookmarksTree)
            {
                sb.AppendLine(PercorreBookmarks(node).ToString());
            }
            return RemoveAllBlankLines(sb);
        }

        private static StringBuilder RemoveAllBlankLines(StringBuilder sb)
        {
            return new StringBuilder().Append(Regex.Replace(sb.ToString(), @"^\s+$[\r\n]*", string.Empty, RegexOptions.Multiline));
        }

        private static StringBuilder PercorreBookmarks(Dictionary<string, object> bookmark)
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendLine(bookmark["Title"].ToString());
            if (bookmark != null && bookmark.ContainsKey("Kids"))
            {
                IList<Dictionary<string, object>> children = (IList<Dictionary<string, object>>) bookmark["Kids"];
                foreach (var bm in children)
                {
                    sb.AppendLine(PercorreBookmarks(bm).ToString());
                }
            }
            return sb;
        }
    }
}