Well, in latest version of Aspose.Cells.GridWeb v220.127.116.110 (you may get it by installing the latest Aspose.Cells for .NET v7.3.5 MSI installer), we have supported more file formats for conversion e.g PDF, ODS, Tab Delimited, HTML etc. So, one can directly save the GridWeb to PDF for other formats.
But, we still recommend you to kindly use Aspose.Cells component rather than directly using Aspose.Cells.GridWeb control for PDF conversion, see the topic:
You may also use PageSetup options before conversion:
Please check the document on how to render one page per sheet in the output PDF:
Note: Aspose.Cells render PDF file based on the print preview that is shown in Ms Excel for the sheets, so if you need to display all the columns in one page, your data will be too small to be read, you may confirm this behavior in Ms Excel, so it might not be worth showing everything in a single page.
"If any possible ways for decreasing the size and show in Lanscape format in PDF while convert from excel to PDF or Convert from AsposeGridWeb to PDF."
If you need to manipulate PDF regarding size of the page or other options, please use Aspose.Pdf product. Please do contact Aspose.Pdf team by using Aspose.Pdf forum, they will help you soon there.