problem in c# asp.net

Question

hi i am using c# asp.net, i have one datalist in my form and in my datalist row i have one dynamic dropdownlist and one edit button. consider while running the form in my dropdown list there are two values such as B.E,MCA.then i am selecting MCA from the dropdownlist and i am clicking the edit button. in this case after clicking that edit button MCA has to be shown in the dropdownlist but instead of that MCA the first value(B.E) has been showing in the dropdown list. this is the problem i am getting. so tell me how to rectify this problem and give me code to do my need. i need that in serverside.please help meeeeeeeeeeeeeeeeeeeeeee