net core 使用 iTextSharp 生成PDF

需求：按数据层级生成PDF文件，要有目录，目录里要有真实的页码，附件内容用表格显示，每页要有页码，大标题 做为封面当独显示一页，

PDF内容

大标题，

目录（里有对应的页码）

正文 里有 表格

每页还有页码

/// <summary>
        /// 生成 pdf 文件
        /// </summary>
        /// <param name="model">实体对象</param>
        /// <param name="caseDetailsViewModels">数据LIST</param>
        /// <param name="TargetPath">目标文件路径</param>
        /// <param name="NewFileName">文件名</param>
        /// <returns></returns>
        private static string createPDF(ViewModel model, List<DetailsViewModel> DetailsViewModels, string TargetPath, string NewFileName)
        {
            string outMergeFile = TargetPath + NewFileName;

            if (Directory.Exists(outMergeFile))
            {
                Directory.Delete(outMergeFile);
            }
            var pageSize = PageSize.A4;
            iTextSharp.text.Document document = new iTextSharp.text.Document(pageSize);
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(outMergeFile, FileMode.Create));
            try
            {
                document.Open();

                #region 字体
                Font BF_Light = FontFactory.GetFont(@"C:\Windows\Fonts\simsun.ttc,0", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);

                Font bigTitle_Light = FontFactory.GetFont(@"C:\Windows\Fonts\simsun.ttc,0", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
                bigTitle_Light.Size = 20;

                Font title_Light = FontFactory.GetFont(@"C:\Windows\Fonts\simsun.ttc,0", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
                title_Light.SetColor(0, 0, 255);
                title_Light.Size = 16;

                Font body_Light = FontFactory.GetFont(@"C:\Windows\Fonts\simsun.ttc,0", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
                body_Light.Size = 12;
                //var titleFont = GetFont();
                //titleFont.SetStyle(Font.BOLD);
                //titleFont.Color = BaseColor.BLACK;
                //titleFont.Size = 16;
                //new Font(baseFont2, 20f) 
                #endregion

                //第一页
                //段落 大标题
                #region 大标题
                var titleParagraph = new Paragraph(new Phrase(model.TitleModel.F_ContentStr, bigTitle_Light));
                float x = 300;
                float y = document.PageSize.Height / 2;
                ColumnText.ShowTextAligned(writer.DirectContent, Element.ALIGN_CENTER, titleParagraph, x, y, 0);
                #endregion

                //第二页
                #region 增加目录页
                document.NewPage();
                var catalogueP = new Paragraph(new Phrase("目录", body_Light));
                //catalogueP.IndentationLeft = 160;
                //document.Add(catalogueP);
                //页头显示的位置
                ColumnText.ShowTextAligned(writer.DirectContent, Element.ALIGN_CENTER, catalogueP, document.PageSize.Width / 2, document.Top, 0);
                foreach (var item in model.TwoTitleList)
                {
                    Chunk leader = new Chunk(new DottedLineSeparator(), 400);//400
                    var F_ContentStrTxt = item.F_ContentStr.Trim();
                    Paragraph pp = new Paragraph(new Phrase("    " + F_ContentStrTxt, BF_Light));
                    pp.Add(leader);
                    pp.Add(new Phrase(!string.IsNullOrEmpty(item.F_Page) ? item.F_Page : "1～1", BF_Light));
                    document.Add(pp);
                }
                #endregion
                //正文
                //第三页
                #region 正文
                int iPageNum = 3;
                int beginPageNum = 3;
                BaseFont baseFont2 = BaseFont.CreateFont(@"C:\Windows\Fonts\simsun.ttc,0", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
                document.NewPage();
                foreach (var item in model.TwoTitleList)
                {
                    iPageNum = writer.PageNumber;
                    //标题
                    document.Add(new Paragraph(new Phrase(item.F_ContentStr, title_Light)));
                    foreach (var itemThree in item.ThreeContentList)
                    {
                        itemThree.F_ContentStr = itemThree.F_ContentStr.Replace("\r\n", string.Empty);
                        //内容
                        if (itemThree.F_ContentStr.Contains("</p>"))
                        {
                            var contentStr = itemThree.F_ContentStr.Replace("<p>", string.Empty);
                            var contentList = contentStr.Split("</p>");
                            foreach (var itemCon in contentList)
                            {
                                var itemConTxt = itemCon.Replace("\n", string.Empty).Trim();
                                var bydyPhrase = new Paragraph(new Phrase("    " + itemConTxt, body_Light));
                                document.Add(bydyPhrase);
                                if (writer.PageNumber > iPageNum)
                                {
                                    writePageNumber(document, writer, BF_Light);
                                }
                            }
                        }
                        else
                        {
                            var txt = itemThree.F_ContentStr.Replace("\n", string.Empty).Trim();
                            document.Add(new Paragraph(new Phrase("    " + txt, body_Light)));
                        }
                    }
                    //if (writer.PageNumber > iPageNum)
                    //{
                    item.F_Page = string.Format("{0}～{1}", iPageNum, writer.PageNumber);
                    iPageNum = writer.PageNumber;
                    //}
                }
                #endregion

                #region 附件
                if (model.FileList != null && model.FileList.Count > 0)
                {
                    var bydyPhrase1 = new Paragraph(new Phrase("    （一）检索结果分析列表", body_Light));
                    document.Add(bydyPhrase1);
                    document.Add(new Paragraph(new Phrase("  ")));

                    int groupNum = 1;
                    foreach (var item in model.FileList)
                    {
                        var keywordTxt = item.Keyword.Replace("\n", string.Empty).Trim();
                        var bydyPhrase = new Paragraph(new Phrase("    " + keywordTxt, body_Light));
                        document.Add(bydyPhrase);
                        document.Add(new Paragraph(new Phrase("  ")));

                        PdfPTable table = new PdfPTable(4);
                        int[] widths = { 40, 20, 20, 20 };
                        table.SetWidths(widths);//设置每列的宽度（求和百分比5,10=1,2）
                                                //为pdfpTable的构造函数传入整数3，pdfpTable被初始化为一个三列的表格
                                                //PdfPCell cell = new PdfPCell(new Phrase("第一行 跨3列", BF_Light));
                                                //cell.Colspan = 6;//跨3列

                        //0=Left, 1=Centre, 2=Right
                        //table.AddCell(cell);
                        PdfPCell cell = new PdfPCell(new Phrase("标题", BF_Light));
                        cell.HorizontalAlignment = 1;
                        table.AddCell(cell);

                        PdfPCell cel2 = new PdfPCell(new Phrase("案号", BF_Light));
                        cel2.HorizontalAlignment = 1;
                        table.AddCell(cel2);

                        PdfPCell cel3 = new PdfPCell(new Phrase("是否加入检索报告", BF_Light));
                        cel3.HorizontalAlignment = 1;
                        table.AddCell(cel3);

                        PdfPCell cel4 = new PdfPCell(new Phrase("未加入检索报告原因", BF_Light));
                        cel4.HorizontalAlignment = 1;
                        table.AddCell(cel4);
                        foreach (var itemKey in item.KeywordFileList)
                        {
                            table.AddCell(new Phrase(itemKey.F_CaseTitle, BF_Light));
                            table.AddCell(new Phrase(itemKey.F_CaseCode.ToString(), BF_Light));
                            table.AddCell(new Phrase(itemKey.F_IsAdd ? "是" : "否", BF_Light));
                            table.AddCell(new Phrase(itemKey.F_NoAddCause, BF_Light));
                            groupNum++;
                        }
                        document.Add(table);
                    }
                }
                #endregion

                #region 生成案例
                if (caseDetailsViewModels != null && caseDetailsViewModels.Count > 0)
                {
                    var bydyPhrase2 = new Paragraph(new Phrase("    （二）检索案例全文", body_Light));
                    document.Add(bydyPhrase2);
                    document.Add(new Paragraph(new Phrase("  ")));

                    foreach (var item in caseDetailsViewModels)
                    {
                        foreach (var itemCase in item.CaseItemList)
                        {
                            //标题
                            itemCase.F_Title = itemCase.F_Title.Replace("\r\n", string.Empty);
                            var F_TitleTxt = itemCase.F_Title.Trim();
                            document.Add(new Paragraph(new Phrase("  " + F_TitleTxt, body_Light)));

                            //内容
                            itemCase.F_Content = itemCase.F_Content.Replace("\r\n", string.Empty);
                            if (itemCase.F_Content.Contains("</p>"))
                            {
                                var contentStr = itemCase.F_Content.Replace("<p>", string.Empty);
                                var contentList = contentStr.Split("</p>");
                                foreach (var itemCon in contentList)
                                {
                                    var itemConTxt = itemCon.Replace("\n", string.Empty).Trim();
                                    var bydyPhrase = new Paragraph(new Phrase("  " + itemConTxt, body_Light));
                                    document.Add(bydyPhrase);
                                    if (writer.PageNumber > iPageNum)
                                    {
                                        writePageNumber(document, writer, BF_Light);
                                    }
                                }
                            }
                            else
                            {
                                var F_ContentTxt = itemCase.F_Content.Replace("\n", string.Empty).Trim();
                                document.Add(new Paragraph(new Phrase("  " + F_ContentTxt, body_Light)));
                            }
                        }
                    }
                }
                #endregion
            }
            catch (Exception ex)
            {
                LogFactory.GetLogger("createReportDetailsPDFCatalogue").Info("createReportDetailsPDFCatalogue 报错" + ex.Message);
            }
            finally
            {
                if (document != null)
                {
                    document.Close();
                }
                if (writer != null)
                {
                    writer.Close();
                }
            }
            return outMergeFile;
        }

        /// <summary>
        /// 写页码
        /// </summary>
        /// <param name="document"></param>
        /// <param name="writer"></param>
        /// <param name="BF_Light"></param>
        private static void writePageNumber(iTextSharp.text.Document document, PdfWriter writer, Font BF_Light)
        {
            Phrase header = new Phrase("第" + (writer.PageNumber).ToString() + "页", BF_Light);// - 1
                                                                                             //页脚显示的位置
            ColumnText.ShowTextAligned(writer.DirectContent, Element.ALIGN_CENTER, header, document.PageSize.Width / 2, document.Bottom, 0);
        }

调用,注意要调用两次，第一次生成时不知道目录里的内容在第几页，第一次在生成时收集页码。这时会生成一个临时文件。第二次生成的目录里的页码才是真实有效的数据。所以要生成两次。

就好比你在写WORD时也是不知道目录里的内容会写在第几次，都是一、二级标题和内容都写完后，再去生成目录的。这里的道理也是一样的。

var fileNameTempPath = createPDF(model, null, uploadPath, fileNameTemp);
var savePath = createPDF(model, caseDetailsViewModels, uploadPath, fileName);

如果有更好的方法请告诉我。