Do NOT refresh gridview dropdownlist on edit

First; I copied the "asp:Label…. " command from the "ItemTemplate" section of the "Model" column and pasted it in the "EditItemTemplate" just above the dropdown list and added the value (Visible="false") to the end of the statement.

Second; I added the following (GridView1_RowDataBound) method to the "aspx.cs" page just above the existing (GridView1_RowUpdating) method and populated it with the following code –

if (e.Row.RowType == DataControlRowType.DataRow)
            {
                if ((e.Row.RowState & DataControlRowState.Edit) > 0)
                {

                    DropDownList DDL2 = e.Row.FindControl("ddlModel") as DropDownList;       // 2nd ddl (Region)

                    Label LBL2 = e.Row.FindControl("Label1") as Label;       // label in "edit" mode on second ddl

                    DDL2.DataBind();
                    DDL2.SelectedValue = Convert.ToString(LBL2.Text);
                }
            }

<%@ Page Title="Cascading Gridview" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="About.aspx.cs" Inherits="WebApplication1.About" %>

<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Customerid" DataSourceID="SqlDataSource1" 
        CellPadding="4" ForeColor="#333333" OnRowUpdating="GridView1_RowUpdating" OnRowDataBound="GridView1_RowDataBound">
        <AlternatingRowStyle BackColor="White" />
        <Columns>
            <%-- Edit Column --%>
            <asp:CommandField ShowEditButton="true" />

            <%-- CustomerId Column --%>
            <asp:BoundField DataField="Customerid" HeaderText="Customerid" InsertVisible="False" ReadOnly="True" SortExpression="Customerid" />

            <%-- Name Column --%>
            <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

            <%-- Manufacturer Column --%>
            <asp:TemplateField HeaderText="Manufacturer" SortExpression="Manufacturer">
                <EditItemTemplate>
                    
                    <%--<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Manufacturer") %>'></asp:TextBox>--%>

                    <%-- Dropdown List --%>
                    <asp:DropDownList ID="ddlManufacturer" runat="server" AutoPostBack="true" DataTextField="Manufacturer"
                        DataValueField="Manufacturer" SelectedValue='<%# Bind("Manufacturer") %>' DataSourceID="SqlDataSource2" >
                    </asp:DropDownList>

                    <%-- SQL DataSource --%>
                    <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:conString %>"
                        SelectCommand="SELECT [Manufacturer] FROM Manufacturer"></asp:SqlDataSource>
                </EditItemTemplate>

                    <%-- Label --%>
                <ItemTemplate>
                    <asp:Label ID="Label1" runat="server" Text='<%# Bind("Manufacturer") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>

            <%-- Model Column --%>
            <asp:TemplateField HeaderText="Model" SortExpression="Model">
                <EditItemTemplate>
                    <%--<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Model") %>'></asp:TextBox>--%>

                     <%-- Label --%>
                    <asp:Label ID="Label1" runat="server" Text='<%# Bind("Model") %>' Visible="false"></asp:Label>

                     <%-- DropDownList --%>
                    <asp:DropDownList ID="ddlModel" runat="server" DataSourceID="SqlDataSource3" DataTextField="Model" DataValueField="Model" >
                    </asp:DropDownList>

                    <%-- Data Source --%>
                    <asp:SqlDataSource ID="SqlDataSource3" runat="server" ConnectionString="<%$ ConnectionStrings:conString %>"
                    SelectCommand="SELECT [Model],[Manufacturer] FROM [Model] " FilterExpression="[Manufacturer]= '{0}'">
                    <FilterParameters><asp:ControlParameter ControlID="ddlManufacturer" Name="Manufacturer" PropertyName="SelectedValue" Type="String" />
                    </FilterParameters>
                    </asp:SqlDataSource>
                </EditItemTemplate>

                <%-- Label --%>
                <ItemTemplate>
                    <asp:Label ID="Label2" runat="server" Text='<%# Bind("Model") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>

            <%-- ID Column --%>
            <asp:BoundField DataField="id" HeaderText="id" SortExpression="id" />

        </Columns>
        <FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
        <HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
        <RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
        <SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
        <SortedAscendingCellStyle BackColor="#FDF5AC" />
        <SortedAscendingHeaderStyle BackColor="#4D0000" />
        <SortedDescendingCellStyle BackColor="#FCF6C0" />
        <SortedDescendingHeaderStyle BackColor="#820000" />
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:conString %>" 
    SelectCommand="SELECT [CustomerId], [Name], [Manufacturer], [Model], [id] FROM [Customers] ORDER BY CustomerId"
    UpdateCommand="UPDATE [Customers] SET [Name]=@Name, [Manufacturer]=@Manufacturer, [Model]=@Model WHERE [CustomerId]=@CustomerId"></asp:SqlDataSource>
</asp:Content>

using System;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication1
{
    public partial class About : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                if ((e.Row.RowState & DataControlRowState.Edit) > 0)
                {

                    DropDownList DDL2 = e.Row.FindControl("ddlModel") as DropDownList;       // 2nd ddl (Region)

                    Label LBL2 = e.Row.FindControl("Label1") as Label;       // label in "edit" mode on second ddl

                    DDL2.DataBind();
                    DDL2.SelectedValue = Convert.ToString(LBL2.Text);
                }
            }
        }
        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            string strModel = ((DropDownList)((GridView)sender).Rows[e.RowIndex].FindControl("ddlModel")).SelectedValue;
            string strManufacturer = ((DropDownList)((GridView)sender).Rows[e.RowIndex].FindControl("ddlManufacturer")).SelectedItem.Value;
            e.NewValues[
            "Model"] = strModel;
            e.NewValues[
            "Manufacturer"] = strManufacturer;
            e.Cancel =
            false;
            GridView gv = (GridView)sender;
            for (int i = 0; i < gv.Columns.Count; i++)
            {
                DataControlFieldCell cell = gv.Rows[e.RowIndex].Cells[i] as DataControlFieldCell;
                gv.Columns[i].ExtractValuesFromCell(e.NewValues, cell,
                DataControlRowState.Edit, true);
            }
        }
    }
}