将Office文档（Word、Excel、Powerpoint）转为pdf格式，有多种实现方式，最常见的就是使用微软的Office组件。步骤如下：
① 打开NuGet包管理器，引用以下四个组件：
MicrosoftOfficeCore
Microsoft.Office.Interop.Word
Microsoft.Office.Interop.Excel
Microsoft.Office.Interop.PowerPoint
② 编写Office帮助类
public static class OfficeHelper { /// <summary> /// Word转换为PDF /// </summary> /// <param name="sourcePath">源文件路径</param> /// <param name="targetPath">目标文件路径</param> /// <param name="exportFormat">导出文件格式</param> /// <returns></returns> public static bool Convert(string sourcePath, string targetPath, Word.WdExportFormat exportFormat) { bool result; object paramMissing = Type.Missing; Word.ApplicationClass wordApplication = new Word.ApplicationClass(); Word.Document wordDocument = new Word.Document(); try { object paramSourceDocPath = sourcePath; string paramExportFilePath = targetPath; Word.WdExportFormat paramExportFormat = exportFormat; bool paramOpenAfterExport = false; Word.WdExportOptimizeFor paramExportOptimizeFor = Word.WdExportOptimizeFor.wdExportOptimizeForPrint; Word.WdExportRange paramExportRange = Word.WdExportRange.wdExportAllDocument; int paramStartPage = 0; int paramEndPage = 0; Word.WdExportItem paramExportItem = Word.WdExportItem.wdExportDocumentContent; bool paramIncludeDocProps = true; bool paramKeepIRM = true; Word.WdExportCreateBookmarks paramCreateBookmarks = Word.WdExportCreateBookmarks.wdExportCreateWordBookmarks; bool paramDocStructureTags = true; bool paramBitmapMissingFonts = true; bool paramUseISO19005_1 = false; wordDocument = wordApplication.Documents.Open( ref paramSourceDocPath, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing); if (wordDocument != null) wordDocument.ExportAsFixedFormat(paramExportFilePath, paramExportFormat, paramOpenAfterExport, paramExportOptimizeFor, paramExportRange, paramStartPage, paramEndPage, paramExportItem, paramIncludeDocProps, paramKeepIRM, paramCreateBookmarks, paramDocStructureTags, paramBitmapMissingFonts, paramUseISO19005_1, ref paramMissing); result = true; } finally { if (wordDocument != null) { wordDocument.Close(ref paramMissing, ref paramMissing, ref paramMissing); } if (wordApplication != null) { wordApplication.Quit(ref paramMissing, ref paramMissing, ref paramMissing); } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); } return result; } /// <summary> /// Excel转换为PDF /// </summary> /// <param name="sourcePath">源文件路径</param> /// <param name="targetPath">目标文件路径</param> /// <param name="exportFormat">导出文件格式</param> /// <returns></returns> public static bool Convert(string sourcePath, string targetPath, Excel.XlFixedFormatType targetType) { bool result; object missing = Type.Missing; Excel.ApplicationClass application = new Excel.ApplicationClass(); Excel.Workbook workBook = new Excel.Workbook(); try { application = new Excel.ApplicationClass(); object target = targetPath; object type = targetType; workBook = application.Workbooks.Open(sourcePath, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing); workBook.ExportAsFixedFormat(targetType, target, Excel.XlFixedFormatQuality.xlQualityStandard, true, false, missing, missing, missing, missing); result = true; } catch { result = false; } finally { if (workBook != null) { workBook.Close(true, missing, missing); } if (application != null) { application.Quit(); } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); } return result; } /// <summary> /// PPT转换为PDF /// </summary> /// <param name="sourcePath">源文件路径</param> /// <param name="targetPath">目标文件路径</param> /// <param name="exportFormat">导出文件格式</param> /// <returns></returns> public static bool Convert(string sourcePath, string targetPath, PowerPoint.PpSaveAsFileType targetFileType) { bool result; object missing = Type.Missing; PowerPoint.ApplicationClass application = new PowerPoint.ApplicationClass(); PowerPoint.Presentation persentation = null; try { application = new PowerPoint.ApplicationClass(); persentation = application.Presentations.Open(sourcePath, MsoTriState.msoTrue, MsoTriState.msoFalse, MsoTriState.msoFalse); persentation.SaveAs(targetPath, targetFileType, MsoTriState.msoTrue); result = true; } catch { result = false; } finally { if (persentation != null) { persentation.Close(); } if (application != null) { application.Quit(); } GC.Collect(); GC.WaitForPendingFinalizers(); GC.Collect(); GC.WaitForPendingFinalizers(); } return result; } }
最后，就可以调用进行转换了。
注意：
①该方式目前只能用于Windows系统
②该方式依赖Microsoft Office软件
③在.net framework和.net core的项目下均可使用（以Win Form项目为例）