PDF拆分(按照页码拆分成多份)C#源码

【实例截图】

【核心代码】

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;


namespace PDF
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        int iPageNum;
        string filePath = "";
        private void button1_Click(object sender, EventArgs e)
        {
            if (filePath == "")
            {
                MessageBox.Show("选择PDF文件无效！", "文件无效！");
            }
            else
            {
                if (numericUpDownEndPageNum.Value > iPageNum)
                {
                    MessageBox.Show("最大页码值有误！请检查！", "页码有误！");
                }
                else if (numericUpDownStartPageNum.Value < 1)
                {
                    MessageBox.Show("最小页码值有误！请检查！", "页码有误！");
                }
                else if (numericUpDownStartPageNum.Value > numericUpDownEndPageNum.Value)
                {
                    MessageBox.Show("最小页码值比最大页码值大！请检查！", "页码有误！");
                }
                else
                {
                    string splitPDFPath = filePath.Remove(filePath.Length - 4) 
                          "("   numericUpDownStartPageNum.Value.ToString() 
                          "-"   numericUpDownEndPageNum.Value.ToString() 
                          ").pdf";
                    int startPageNum = int.Parse(numericUpDownStartPageNum.Value.ToString());
                    int endPageNum = int.Parse(numericUpDownEndPageNum.Value.ToString());
                    copypdf(startPageNum, endPageNum, filePath, splitPDFPath);
                    MessageBox.Show("处理完毕！","提示");
                }   
            }
        }

        private void copypdf(int StartPage, int EndPage, string file1, string splitFileName)
            //将file1中页码StartPage到EndPage的文件拷贝至splitFileName          
        {
            iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(file1);
            Document document = new Document(reader.GetPageSizeWithRotation(StartPage));
            //创建document对象
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(splitFileName, FileMode.Create)); 
            //实例化document对象
            document.Open();
            int rotation;
            PdfContentByte cb = writer.DirectContent;
            PdfImportedPage page;
            while (StartPage <= EndPage)
            {
                document.SetPageSize(reader.GetPageSizeWithRotation(StartPage));
                document.NewPage();
                page = writer.GetImportedPage(reader, StartPage);
                rotation = reader.GetPageRotation(StartPage);
                if (rotation == 90 || rotation == 270)
                {
                    //document.NewPage();
                    if (rotation == 90)
                    {
                        cb.AddTemplate(page, 0, -1f, 1f, 0, 0, reader.GetPageSizeWithRotation(StartPage).Height);
                    }
                    if (rotation == 270)
                    {
                        cb.AddTemplate(page, 0, 1.0F, -1.0F, 0, reader.GetPageSizeWithRotation(StartPage).Width, 0);
                    }
                }
                else
                {
                    cb.AddTemplate(page, 1f, 0, 0, 1f, 0, 0);
                }
                StartPage  ;
            }
            try
            {
                document.Close();
                reader = null;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }
        
        private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog myBlockDialog = new OpenFileDialog();
            myBlockDialog.Filter = "PDF文件(*.pdf)|*.pdf";
            myBlockDialog.Title = "打开PDF文件";
            myBlockDialog.ShowDialog();

            filePath = myBlockDialog.FileName;
            if (filePath == "")
            {
                MessageBox.Show("选择PDF文件无效！", "文件无效！");
                //Application.Exit();
            }
            labSelectInfo.Text = "已选择PDF文件："   filePath;

            //iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(filePath);
            Document document = new Document();
            //PdfWriter.GetInstance(document,new FileStream(filePath,FileMode.Open));
            PdfReader reader = new PdfReader(filePath);
            iPageNum = reader.NumberOfPages;
            reader.Close(); //不关闭会一直占用pdf资源，对接下来的操作会有影响
            //PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(splitFileName, FileMode.Create)); 
            labMaxPageNum.Text = @"/"   iPageNum.ToString();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Document doc = new Document(PageSize.A4);
            PdfWriter.GetInstance(doc,new FileStream("test1.pdf",FileMode.Create));
            doc.Open();
            doc.Add(new Paragraph("Hello!"));
            doc.Close();
        }

        private void numericUpDownStartPageNum_ValueChanged(object sender, EventArgs e)
        {

        }
    }
}