public bool WordToPDF(string sourcePath, string targetPath)
    {
      bool result = false;
      Microsoft.Office.Interop.Word.Application application = new Microsoft.Office.Interop.Word.Application();
      Document document = null;
      try
      {
       application.Visible = false;
       document = application.Documents.Open(sourcePath);
       document.ExportAsFixedFormat(targetPath, WdExportFormat.wdExportFormatPDF);
       result = true;
      }
      catch (Exception e)
      {
       Console.WriteLine(e.Message);
       result = false;
      }
      finally
      {
       document.Close();
      }
      return result;
    }

public bool WordToPdfWithWPS(string sourcePath, string targetPath)
    {
      WPS.ApplicationClass app = new WPS.ApplicationClass();
      WPS.Document doc = null;
      try
      {
       doc = app.Documents.Open(sourcePath, true, true, false, null, null, false, "", null, 100, 0, true, true, 0, true);
       doc.ExportPdf(targetPath, "", "");
      }
      catch (Exception ex)
      {
       Console.WriteLine(ex.Message);
       return false;
      }
      finally
      {
       doc.Close();
      }
      return true;
    }