how to validate the contents of excel file after uploading it.

hi Experts,

we have a requirement in which we need to create business transactions with the data in the excel file after it was uploaded. we are creating this transactions(BP,LEAD..) in webui -marketing professional role-external lists. what i have to do is, after uploading the data from excel file, i need to check for the mandatory fields in the data ,if anything is missing then i need to display the error message to the user. i am new to this webclinet frame work. please help me in achieving this functioanlity.any code snippet would be very helpful.

THANKS IN ADVANCE.