For each does not working properly?

Question

Hi friends i m developing attendance percentage module in student automation system.Percentage will be calculated based on monthly wise.here i m using foreach statement.if i selects section "A"(contains 5 no of students) means all student attendance percentage will be displayed on grid view.the percentage calculation are done to first name students.my problem is the same percentage are repeated to all student..can anyone correct my problem......Thanks in advance..

here with i had attached the sample piece of code..