Hi Yubo!
This is very old post but i tought i will still reply. Maybe this will help you or some other.
I have field called account_disabled in database. Values on that field are 0 if not disabled and 1 if account is disabled.
I have checkbox inside of DataList component and it's EditItemTemplate. So i needed to make that box "checked" if the value is 1. Below you can see how i did manage to do it
1 <input type="checkbox" name="chkDisabled" id="chkDisabled" <%#Replace(Replace(Eval("account_disabled"), "1", "checked"), "0", "")%> />
Im not sure if it will work with asp:CheckBox..
Sorry about my poor English :)