http://www.aspsnippets.com/Articles/Enable-disable-TextBox-in-GridView-when-checkbox-is-selected-checked-in-ASPNet.aspx

used that as source but it is not working

 <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <asp:GridView ID="grdVESONV" runat="server" BackColor="White" BorderColor="#cbcdcb"
            BorderStyle="None" BorderWidth="1px" CellPadding="4" ForeColor="Black" GridLines="Both"
            Font-Size="Smaller" EmptyDataText="No Records Found" Width="100%" ShowHeaderWhenEmpty="True"
            AutoGenerateColumns="false" OnRowCreated="grdVESONV_RowCreated" OnRowDataBound="grdVESONV_RowDataBound">
            <EmptyDataRowStyle BackColor="white" ForeColor="black" />
            <EmptyDataTemplate>
                No Data Found.</EmptyDataTemplate>
            <AlternatingRowStyle BackColor="White" />
            <Columns>
                <asp:TemplateField>
                    <HeaderTemplate>
                        <asp:CheckBox ID="chkHeader" runat="server" />
                    </HeaderTemplate>
                    <ItemTemplate>
                        <asp:CheckBox ID="chkRow" runat="server" />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="VES Adjustment">
                    <ItemTemplate>
                        <asp:TextBox ID="txtVESAdj" runat="server" Text='<%# Eval("VES Adjustment") %>' Enabled="false"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        //Enable Disable all TextBoxes when Header Row CheckBox is checked.
        $("[id*=chkHeader]").bind("click", function () {
            var chkHeader = $(this);

            //Find and reference the GridView.
            var grid = $(this).closest("table");

            //Loop through the CheckBoxes in each Row.
            $("td", grid).find("input[type=checkbox]").each(function () {

                //If Header CheckBox is checked.
                //Then check all CheckBoxes and enable the TextBoxes.
                if (chkHeader.is(":checked")) {
                    $(this).attr("checked", "checked");
                    var td = $("td", $(this).closest("tr"));
                    td.css({ "background-color": "#D8EBF2" });
                    $("input[type=text]", td).removeAttr("disabled");
                } else {
                    $(this).removeAttr("checked");
                    var td = $("td", $(this).closest("tr"));
                    td.css({ "background-color": "#FFF" });
                    $("input[type=text]", td).attr("disabled", "disabled");
                }
            });
        });

        //Enable Disable TextBoxes in a Row when the Row CheckBox is checked.
        $("[id*=chkRow]").bind("click", function () {

            //Find and reference the GridView.
            var grid = $(this).closest("table");

            //Find and reference the Header CheckBox.
            var chkHeader = $("[id*=chkHeader]", grid);

            //If the CheckBox is Checked then enable the TextBoxes in thr Row.
            if (!$(this).is(":checked")) {
                var td = $("td", $(this).closest("tr"));
                td.css({ "background-color": "#FFF" });
                $("input[type=text]", td).attr("disabled", "disabled");
            } else {
                var td = $("td", $(this).closest("tr"));
                td.css({ "background-color": "#D8EBF2" });
                $("input[type=text]", td).removeAttr("disabled");
            }

            //Enable Header Row CheckBox if all the Row CheckBoxes are checked and vice versa.
            if ($("[id*=chkRow]", grid).length == $("[id*=chkRow]:checked", grid).length) {
                chkHeader.attr("checked", "checked");
            } else {
                chkHeader.removeAttr("checked");
            }
        });
    });
</script>