public void PrintWordToPDF(string fileName)
        {
            string progid = "Bullzip.PDFPrinterSettings";

            System.Type oType = System.Type.GetTypeFromProgID(progid);

            object obj_printer_settings = System.Activator.CreateInstance(oType);

            //找出虚拟打印机
            string PrinterName = (string)oType.InvokeMember("GetPrinterName", System.Reflection.BindingFlags.InvokeMethod, null, obj_printer_settings, null);

            Microsoft.Office.Interop.Word.ApplicationClass word = new Microsoft.Office.Interop.Word.ApplicationClass();

            Type wordType = word.GetType();

            //打开WORD文档
            Microsoft.Office.Interop.Word.Documents docs = word.Documents;           

            Type docsType = docs.GetType();

            object objDocName = fileSavePath+"\\"+fileName;

            Microsoft.Office.Interop.Word.Document doc = (Microsoft.Office.Interop.Word.Document)docsType.InvokeMember("Open", System.Reflection.BindingFlags.InvokeMethod, null, docs, new Object[] { objDocName, true, true });

            doc.Application.ActivePrinter = PrinterName;

            Type docType = doc.GetType();

            object printFileName = fileSavePath+"\\"+GetFileName(fileName)+ ".pdf";

            //打印输出
            docType.InvokeMember("PrintOut", System.Reflection.BindingFlags.InvokeMethod, null, doc, new object[] { false, false, Microsoft.Office.Interop.Word.WdPrintOutRange.wdPrintAllDocument, printFileName });

            //退出WORD
            wordType.InvokeMember("Quit", System.Reflection.BindingFlags.InvokeMethod, null, word, null);

        }