PDF输出图片

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.IO;
using System.Windows.Forms;
using System.Diagnostics;

using PdfSharp;
using PdfSharp.Pdf;
using PdfSharp.Drawing;

using PdfSharp.Pdf.Advanced;
using PdfSharp.Pdf.IO;
using System.Collections;

 /// <summary>
        /// Currently extracts only JPEG images.
        /// </summary>
        static void ExportImage(PdfDictionary image, ref int count)
        {
            string filter = image.Elements.GetName("/Filter");

            ExportJpegImage(image, ref count);

        }
       static string imgPath = "";
        /// <summary>
        /// Exports a JPEG image.
        /// </summary>
        static void ExportJpegImage(PdfDictionary image, ref int count)
        {
            // Fortunately JPEG has native support in PDF and exporting an image is just writing the stream to a file.
            byte[] stream = image.Stream.Value;
            FileStream fs = new FileStream(String.Format("{1}/Image{0}.jpg", count++,imgPath), FileMode.Create, FileAccess.Write);
            BinaryWriter bw = new BinaryWriter(fs);
            bw.Write(stream);
            bw.Close();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            const string filename = @"E:\1\aa\000.pdf";
            imgPath = Path.GetDirectoryName(filename);
            PdfDocument document = PdfReader.Open(filename);

            int imageCount = 0;
            // Iterate pages
            foreach (PdfPage page in document.Pages)
            {
                // Get resources dictionary
                PdfDictionary resources = page.Elements.GetDictionary("/Resources");
                if (resources != null)
                {
                    // Get external objects dictionary
                    PdfDictionary xObjects = resources.Elements.GetDictionary("/XObject");
                    if (xObjects != null)
                    {
                        ICollection<PdfItem> items = xObjects.Elements.Values;
                        // Iterate references to external objects
                        foreach (PdfItem item in items)
                        {
                            PdfReference reference = item as PdfReference;
                            if (reference != null)
                            {
                                PdfDictionary xObject = reference.Value as PdfDictionary;
                                // Is external object an image?
                                if (xObject != null && xObject.Elements.GetString("/Subtype") == "/Image")
                                {
                                    ExportImage(xObject, ref imageCount);
                                }
                            }
                        }
                    }
                }
            }
         }