利用Aspose转PDF

添加引用：

using Aspose.Cells;
using Aspose.Slides;
using Aspose.Words;

/// <summary>
        /// PPT转PDF
        /// </summary>
        /// <param name="InPath">输入路径</param>
        /// <param name="OutPath">输出路径</param>
        public void PPT_PDF(string InPath, string OutPath)
        {
            Presentation ppt = new Presentation(InPath);
            ppt.Save(OutPath, Aspose.Slides.Export.SaveFormat.Pdf);
        }
        /// <summary>
        /// Word转PDF
        /// </summary>
        /// <param name="InPath"></param>
        /// <param name="OutPath"></param>
        public void Word_PDF(string InPath, string OutPath)
        {
            Document doc = new Document(InPath);
            doc.Save(OutPath, Aspose.Words.SaveFormat.Pdf);
        }
        /// <summary>
        /// Excel转PDF
        /// </summary>
        /// <param name="InPath"></param>
        /// <param name="OutPath"></param>
        public void Excel_PDF(string InPath, string OutPath)
        {
            Workbook excel = new Workbook(InPath);
            excel.Save(OutPath, Aspose.Cells.SaveFormat.Pdf);
        }