Serial port communication with vb.net

Hi
i want to store the data coming through serial port in any variable. I done to the extent that data is coming through serial port and we can see it in listbox in the form in vb.net. and also i connect vb.net with access database.

But now i want to compare this data with the data in the database. can any body help me. i will be very thankful to him. i need code.

Thanks
Faizan Naseem