Gridview approve and reject button

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RequestNo" OnRowCommand="GridView1_RowCommand">
            <Columns>
                <asp:ButtonField CommandName="Update" Text="Approve" ButtonType="Button" />
                <asp:ButtonField ButtonType="Button" Text="Disapprove" />
                <asp:BoundField DataField="RequestNo" HeaderText="RequestNo" InsertVisible="False"
                    ReadOnly="True" SortExpression="RequestNo" />
                <asp:BoundField DataField="Date" HeaderText="Date" SortExpression="Date" />
                <asp:BoundField DataField="FullName" HeaderText="FullName" ReadOnly="True" SortExpression="FullName" />
                <asp:BoundField DataField="Position" HeaderText="Position" SortExpression="Position" />
                <asp:BoundField DataField="Department" HeaderText="Department" SortExpression="Department" />
                <asp:BoundField DataField="Section" HeaderText="Section" SortExpression="Section" />
                <asp:BoundField DataField="Employee" HeaderText="Employee" SortExpression="Employee" />
                <asp:BoundField DataField="Request" HeaderText="Request" SortExpression="Request" />
                <asp:BoundField DataField="Status" HeaderText="Status" SortExpression="Status" />
                <asp:BoundField DataField="Comment" HeaderText="Comment" SortExpression="Comment" />
                <asp:BoundField DataField="Account" HeaderText="Account" SortExpression="Account" />
            </Columns>
        </asp:GridView>

protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
        {
            if (e.CommandName == "Update")
            {
                int index = Convert.ToInt32(e.CommandArgument);
                GridViewRow row = GridView1.Rows[index];  // row which u have created..
                string requestNo = row.Cells[2].Text;
                // similarly u can get all the values of the row..
                // u can do ur stuff here...
            }

            if (e.CommandName == "") // other command names etc etc...
            { }
        }