itextsharp操作

using System.Collections.Generic;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace Pdf
{
    /// <summary>
    /// Pdf文件信息
    /// 印刷文件最多两页，且每页的长宽一样的
    /// </summary>
    public class PdfFileInfo
    {
        public string path { get; set; }

        public float width { get; set; }

        public float height { get; set; }

        public float X { get; set; }

        public float Y { get; set; }
    }

    /// <summary>
    /// pdf操作核心类
    /// </summary>
    public class PdfMange
    {
        /// <summary>
        /// 读取多个pdf文件，按照每个pdf文件顺序+页面顺序合并到一个pdf文件中
        /// </summary>
        /// <param name="fileList"></param>
        /// <param name="targetFile"></param>
        public static void ComBineMoreToOne(string[] fileList, string targetFile)
        {
            PdfReader reader;
            Document document = new Document();
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(targetFile, FileMode.Create));
            document.Open();

            PdfContentByte cb = writer.DirectContent;
            PdfImportedPage newPage;

            for (int i = 0; i < fileList.Length; i++)
            {
                reader = new PdfReader(fileList[i]);
                int iPageNum = reader.NumberOfPages;

                for (int j = 1; j <= iPageNum; j++)
                {
                    newPage = writer.GetImportedPage(reader, j);
                    document.NewPage();
                    cb.AddTemplate(newPage, 0, 0);
                }
            }
            document.Close();
        }
        /// <summary>
        /// 读取多个pdf文件，按照每个pdf文件顺序+页面顺序合并到一个pdf文件中的一页上，并且自动适应大小排序
        /// 1英寸=72磅     2.54厘米=1英寸   pdf单位磅
        /// </summary>
        /// <param name="fileList"></param>
        /// <param name="targetFile"></param>
        public static void ComBineMoreToOnePage(IList<PdfFileInfo> fileList, string targetFile)
        {
            float[] urx2 = GetUrxy(fileList);
            float urx = urx2[0], ury = urx2[1];
            int marginLeft = 0, marginRight = 0, marginTop = 0, marginBottom = 0;
            iTextSharp.text.Rectangle pagesize = new iTextSharp.text.Rectangle(urx, ury);
            Document document = new Document(pagesize, marginLeft, marginRight, marginTop, marginBottom);
            PdfReader reader;
            PdfImportedPage newPage;
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(targetFile, FileMode.Create));
            document.Open();
            PdfContentByte cb = writer.DirectContent;
            //=================================关键复制pdf内容代码段Start===============================================
            foreach (PdfFileInfo info in fileList)
            {
                reader = new PdfReader(info.path);
                int PageNum = reader.NumberOfPages;
                for (int j = 1; j <= PageNum; j++)
                {
                    if (j % 2 != 0&&j<3)//印刷行业规定最多只有2页，且只有一页的第二页要空
                    {
                        newPage = writer.GetImportedPage(reader, j);
                        cb.AddTemplate(newPage, info.X, info.Y);
                    }

                }
            }
            document.NewPage();
            foreach (PdfFileInfo info in fileList)
            {
                reader = new PdfReader(info.path);
                int PageNum = reader.NumberOfPages;
                for (int j = 1; j <= PageNum; j++)
                {
                    if (j % 2 == 0 && j < 3)//印刷行业规定最多只有2页，且只有一页的第二页要空
                    {
                        newPage = writer.GetImportedPage(reader, j);
                        cb.AddTemplate(newPage, info.X, info.Y);
                    }

                }
            }
            //=================================关键复制pdf内容代码段end===============================================
            document.Close();
        }

        public static float[] GetUrxy(IList<PdfFileInfo> fileList)
        {
            IList<float> x = new List<float>();
            IList<float> y = new List<float>();
            foreach (PdfFileInfo info in fileList)
            {
                x.Add(info.width + info.X);


                y.Add(info.height + info.Y);
            }

            for (int i = 0; i < x.Count; i++)
            {
                float temp = x[i];
                for (int j = 0; j < x.Count; j++)
                {
                    if (x[j] < x[i])
                    {
                        x[i] = x[j];
                        x[j] = temp;
                    }
                }
            }

            for (int i = 0; i < y.Count; i++)
            {
                float temp = y[i];
                for (int j = 0; j < y.Count; j++)
                {
                    if (y[j] < y[i])
                    {
                        y[i] = y[j];
                        y[j] = temp;
                    }
                }
            }

            float[] result = { x[0], y[0] };

            return result;
        }

        /// <summary>
        /// 计算pdf 毫米转磅
        /// </summary>
        /// <param name="size"></param>
        /// <returns></returns>
        public static float GetPdfSize(float size)
        {
            return (size / 10) / (float)2.54*(float)72;
        }

        //==============================================================================================================================================
    }
}

/// <summary>
        /// 合并多个pdf文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button4_Click(object sender, EventArgs e)
        {
            List<PdfFileInfo> fileList = new List<PdfFileInfo>();
            PdfFileInfo info = new PdfFileInfo();
            info.path = "c://41.pdf";
            info.X = 0;
            info.Y = 0;
            info.width = PdfMange.GetPdfSize(210);
            info.height = PdfMange.GetPdfSize(297);
            fileList.Add(info);

            PdfFileInfo info2 = new PdfFileInfo();
            info2.path = "c://5.pdf";
            info2.X = PdfMange.GetPdfSize(210); 
            info2.Y = 0;
            info2.width = PdfMange.GetPdfSize(210);
            info2.height = PdfMange.GetPdfSize(297);
            fileList.Add(info2);

            PdfFileInfo info3 = new PdfFileInfo();
            info3.path = "c://442.pdf";
            info3.X = PdfMange.GetPdfSize(210*2); ;
            info3.Y = 0;
            info3.width = PdfMange.GetPdfSize(210);
            info3.height = PdfMange.GetPdfSize(297);
            fileList.Add(info3);



            PdfMange.ComBineMoreToOnePage(fileList, "c://newpdf.pdf");

        }