hi..i created the checkboxes for  datagridview which displays at run time... "when i click on 1st checkbox it is checking and when i click on 2nd checkbox its also checking but my requirement is "when i click on 2nd checkbox  the 1st checkbox "TICKMARK(checked)" want to become false(unchecked)".. plz give help in c#.net

i would suggest that you are using the wrong control here , it would be easier to use a radio button list control

ie <asp:RadioButtonList id=RadioButtonList1 runat="server">
            <asp:ListItem>Yes</asp:ListItem>
            <asp:ListItem>No</asp:ListItem>
     </asp:RadioButtonList>

This will give you the functionality you require only allowing one selection

no i've 2 do with checkbox only?plz help for checkboxes.............

Hi,

The Check box is must then write some logic javascript.to do your needs.