How to edit rows values in gridview?

<asp:GridView ID="grdbasetype" runat="server" AutoGenerateColumns="False" Style="width: 100%"
                                                CellPadding="4" ForeColor="#333333" GridLines="None" BorderColor="MidnightBlue"
                                                BorderStyle="Solid" BorderWidth="2px" Font-Names="Verdana" Font-Size="Small"
                                                AllowPaging="true" PageSize="10" OnPageIndexChanging="grdbasetype_PageIndexChanging"
                                                DataKeyNames="basetype" DataSourceID="SqlDataSource1">
                                                <Columns>
                                                    <asp:TemplateField HeaderText="Select">
                                                        <ItemTemplate>
                                                            <asp:CheckBox ID="chkCheck" runat="server" AutoPostBack="true" CausesValidation="False"
                                                                ToolTip='<%# ((GridViewRow)Container).RowIndex + 1%>' />
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:ButtonField HeaderText="Edit" Text="Edit" />
                                                    <asp:ButtonField HeaderText="Delete" Text="Delete" />
                                                    <%--<asp:ButtonField CommandName="Edit" HeaderText="Edit" Text="Edit" />
                                                    <asp:ButtonField CommandName="Update" HeaderText="Update" Text="Update" />
                                                    <asp:ButtonField CommandName="Insert" HeaderText="Insert" Text="Insert" />
                                                    <asp:BoundField DataField="modelname" HeaderText="Model Name" SortExpression="modelname" />
                                                    <asp:BoundField DataField="basetype" HeaderText="Base Type" SortExpression="basetype" />
                                                    <asp:BoundField DataField="description" HeaderText="Description" SortExpression="description" />
                                                    <asp:BoundField DataField="rs" HeaderText="Rupees" SortExpression="rs" />
                                                    <asp:BoundField DataField="euro" HeaderText="Euro" SortExpression="euro" />
                                                    <asp:BoundField DataField="dollar" HeaderText="Dollar" SortExpression="dollar" />
                                                    <asp:BoundField DataField="modelid" HeaderText="Model Id" SortExpression="modelid" />--%>
                                                    <asp:TemplateField HeaderText="Model Name">
                                                        <EditItemTemplate>
                                                            <asp:Label ID="lblModelname" runat="server" Style="text-align: left" Text='<%# Eval("modelname") %>'></asp:Label>
                                                        </EditItemTemplate>
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblModelname" runat="server" Style="text-align: left" Text='<%# Bind("modelname") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:TemplateField HeaderText="Base Type ">
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblbasetype" runat="server" Style="text-align: left" Text='<%# Eval("basetype") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:TemplateField HeaderText="Description">
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblDescription" runat="server" Style="text-align: left" Text='<%# Eval("description") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:TemplateField HeaderText="Rupees">
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblRupees" runat="server" Style="text-align: left" Text='<%# Eval("rs") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:TemplateField HeaderText="Euro">
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblEuro" runat="server" Style="text-align: left" Text='<%# Eval("euro") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                    <asp:TemplateField HeaderText="Dollar">
                                                        <ItemTemplate>
                                                            <asp:Label ID="lblDollar" runat="server" Style="text-align: left" Text='<%# Eval("dollar") %>'></asp:Label>
                                                        </ItemTemplate>
                                                    </asp:TemplateField>
                                                </Columns>
                                                <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                                                <RowStyle BackColor="#EFF3FB" />
                                                <EditRowStyle BackColor="#2461BF" />
                                                <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                                                <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                                                <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                                                <AlternatingRowStyle BackColor="White" />
                                            </asp:GridView>
                                            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:OrionConnectionString %>"
                                                DeleteCommand="DELETE FROM [mbasetype] WHERE [basetype] = @basetype"
                                                UpdateCommand="UPDATE [mbasetype] SET [modelname] = @modelname, [description] = @description ,[rs]=@rs, [euro]=@euro, [dollar]=@dollar WHERE [basetype] = @basetype">
                                                <DeleteParameters>
                                                    <asp:Parameter Name="basetype" Type="String" />
                                                </DeleteParameters>
                                                <UpdateParameters>
                                                    <asp:Parameter Name="modelname" Type="String" />
                                                    <asp:Parameter Name="basetype" Type="String" />
                                                    <asp:Parameter Name="description" Type="String" />
                                                    <asp:Parameter Name="rs" Type="Double" />
                                                    <asp:Parameter Name="dollar" Type="Double" />
                                                    <asp:Parameter Name="euro" Type="Double" />
                                                    <asp:Parameter Name="modelid" Type="String" />
                                                </UpdateParameters>
                                            </asp:SqlDataSource>