office文件在线预览，模仿网易邮箱在线预览的

  /// <summary>
    /// 转换压缩文件，以便于预览（图片大小调整，office、pdf转成swf）
    /// </summary>
    /// <param name="sfilePath">真实文件路径（虚拟），含文件名，精确到网站根目录</param>
    /// <param name="sfileExtention">真实的文件扩展名，要判断如何转换</param>
    /// <param name="showWait">真是否显示提示等待转换信息，默认不提示</param>
    public static void FileConvert(string sfilePath, string sfileExtention, bool showWait = false)
    {
        string PfilePath = HttpContext.Current.Server.MapPath(Path.GetDirectoryName(sfilePath));//当前操作的物理路径
        string PfileName = Path.GetFileName(sfilePath);// 当前操作的文件名
        string PfileExtention = sfileExtention.ToLower();// 当前操作的文件扩展名
        if (File.Exists(PfilePath + "\\swf\\" + PfileName + ".swf"))
        { return; }
        else
        {
            if (!Directory.Exists(PfilePath + "\\swf\\")) { Directory.CreateDirectory((PfilePath + "\\swf\\")); }
            try
            {
                switch (DocuType(PfileExtention))
                {
                    case TypeOfDocu.office:
                        if (showWait)
                        {
                            System.Text.StringBuilder StrB = new System.Text.StringBuilder(185);
                            StrB.Append("<div style=‘color: #0000CC; font-size: 14px;‘>文档需转换格式，才可以在线预览。<br /><br />转换中，马上就好，请稍后……</div>");
                            StrB.Append("<div style=‘color:white;‘>0000000000000000000000000000000000000000000000000您是第一个浏览的人</div>");//兼容IE256字符才显示，这里180就可以
                            HttpContext.Current.Response.Write(StrB.ToString());
                            HttpContext.Current.Response.Flush();
                        }
                        //将office文件转换成PDF,保存到swf文件夹下
                        string pdfFileName = PfileName + ".pdf";
                        string fileOutPath = PfilePath + "\\swf\\" + pdfFileName;
                        ExportPdf(PfilePath + "\\" + PfileName, fileOutPath, PfileExtention);
                        //切记，使用pdf2swf.exe 打开的文件名之间不能有空格，否则会失败
                        string cmdStr = HttpContext.Current.Server.MapPath("~/SWF/pdf2swf.exe");
                        string savePath = PfilePath + "\\swf\\";
                        //string saveSWFPath = HttpContext.Current.Server.MapPath("~/SWF/");
                        //将PDF文件转换成SWF格式文件
                        string sourcePath = @"""" + savePath + pdfFileName + @"""";//要转换的pdf文件路径
                        string targetPath = @"""" + savePath + PfileName + ".swf" + @"""";//转换之后swf文件存放的目标路径
                        //@"""" 四个双引号得到一个双引号，如果你所存放的文件所在文件夹名有空格的话，要在文件名的路径前后加上双引号，才能够成功
                        // -t 源文件的路径
                        // -s 参数化（也就是为pdf2swf.exe 执行添加一些窗外的参数(可省略)）
                        string argsStr = " -p 1-100 -t " + sourcePath + " -s flashversion=9 -o " + targetPath;
                        //执行pdf到swf的转换
                        ExcutedCmd(cmdStr, argsStr);
                        File.Delete(savePath + pdfFileName);
                        break;
                    case TypeOfDocu.pdf:
                        cmdStr = HttpContext.Current.Server.MapPath("~/SWF/pdf2swf.exe");
                        sourcePath = @"""" + PfilePath + "\\" + PfileName + @"""";
                        targetPath = @"""" + PfilePath + "\\swf\\" + PfileName + ".swf" + @"""";
                        argsStr = " -p 1-100 -t " + sourcePath + " -s flashversion=9 -o " + targetPath;
                        ExcutedCmd(cmdStr, argsStr);
                        break;
                    case TypeOfDocu.jpg:
                        if (!Directory.Exists(PfilePath + "\\img\\")) { Directory.CreateDirectory((PfilePath + "\\img\\")); }
                        ImageSize(900, 0, PfilePath + "\\" + PfileName, PfilePath + "\\img\\" + PfileName + ".jpg", false);
                        break;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
    }


    private static void ExcutedCmd(string cmd, string args)
    {
        using (Process p = new Process())
        {
            ProcessStartInfo psi = new ProcessStartInfo(cmd, args);
            psi.WindowStyle = ProcessWindowStyle.Hidden;
            p.StartInfo = psi;
            p.Start();
            p.WaitForExit();
        }
    }

    private static bool ExportPdf(string fileName, string outputFileName, string fileExt)
    {
        if (string.IsNullOrEmpty(fileName) || string.IsNullOrEmpty(outputFileName))
            return false;
        if (!File.Exists(fileName))
            return false;
        string formatExtension = Path.GetExtension(outputFileName);
        if (string.IsNullOrEmpty(fileExt) || string.IsNullOrEmpty(formatExtension))
            return false;
        if (formatExtension != ".pdf")
            return false;
        switch (fileExt)
        {
            case "doc":
            case "docx":
                return WordExportAsPdf(fileName, outputFileName);
            case "xls":
            case "xlsx":
                return ExcelExportAsPdf(fileName, outputFileName);
            case "ppt":
            case "pptx":
                return PowerPointExportAsPdf(fileName, outputFileName);
            default:
                return false;
        }
    }


    /// <summary>
    /// 转换为pdf文件，适合（.doc、.docx、.mht、.htm文件类型）
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="outputFileName"></param>
    /// <returns></returns>
    private static bool WordExportAsPdf(string fileName, string outputFileName)
    {
        bool isSucceed = false;
        Word.WdExportFormat fileFormat = Microsoft.Office.Interop.Word.WdExportFormat.wdExportFormatPDF;
        Word._Application wordApp = null;
        if (wordApp == null) wordApp = new Word.Application();
        Word._Document wordDoc = null;

        try
        {
            wordDoc = wordApp.Documents.Open(fileName);
            wordDoc.ExportAsFixedFormat(outputFileName, fileFormat);
            isSucceed = true;
        }

        finally
        {
            if (wordDoc != null)
            {
                wordDoc.Close();
                wordDoc = null;
            }
            if (wordApp != null)
            {
                wordApp.Quit();
                wordApp = null;
            }
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }
        return isSucceed;
    }


    /// <summary>
    /// 转换为pdf文件，适合（.xls、.xlsx文件类型）
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="outputFileName"></param>
    /// <returns></returns>
    private static bool ExcelExportAsPdf(string fileName, string outputFileName)
    {
        bool isSucceed = false;
        Excel.XlFixedFormatType fileFormat = Microsoft.Office.Interop.Excel.XlFixedFormatType.xlTypePDF;
        Excel.Application excelApp = null;
        if (excelApp == null) excelApp = new Excel.Application();
        Excel.Workbook workBook = null;

        try
        {
            workBook = excelApp.Workbooks.Open(fileName);
            workBook.ExportAsFixedFormat(fileFormat, outputFileName);
            isSucceed = true;
        }

        finally
        {
            if (workBook != null)
            {
                workBook.Close();
                workBook = null;
            }
            if (excelApp != null)
            {
                excelApp.Quit();
                excelApp = null;
            }
            GC.Collect();
            GC.WaitForPendingFinalizers();
            KillExcel();
        }
        return isSucceed;
    }
    /// <summary>
    /// EXCEL进程无法正常退出
    /// </summary>
    private static void KillExcel()
    {
        Process[] pp = Process.GetProcessesByName("EXCEL");
        foreach (Process p in pp)
        {
            if (p.SessionId == 0)
            { p.Kill(); }
        }
    }

    /// <summary>
    /// 转换为pdf文件，适合（.ppt、pptx文件类型）
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="outputFileName"></param>
    /// <returns></returns>
    private static bool PowerPointExportAsPdf(string fileName, string outputFileName)
    {
        bool isSucceed = false;
        PowerPoint.PpFixedFormatType fileFormat = PowerPoint.PpFixedFormatType.ppFixedFormatTypePDF;

        PowerPoint.Application pptxApp = null;
        if (pptxApp == null) pptxApp = new PowerPoint.Application();
        PowerPoint.Presentation presentation = null;

        try
        {
            presentation = pptxApp.Presentations.Open(fileName, MsoTriState.msoTrue, MsoTriState.msoFalse, MsoTriState.msoFalse);
            presentation.ExportAsFixedFormat(outputFileName, fileFormat);
            isSucceed = true;
        }

        finally
        {
            if (presentation != null)
            {
                presentation.Close();
                presentation = null;
            }
            if (pptxApp != null)
            {
                pptxApp.Quit();
                pptxApp = null;
            }
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }
        return isSucceed;
    }