DataBind to a static dropdown in Gridview is not working

I have crated a screen with a Grid. The Grid contains a dropdown along with some textbox fields. They all are fetched from same table.
I am able to select a value in dropdownlist and it updates the database correctly . But once updated , it does not display correctly back on screen. It displays the first Item in the dropdownlist. The text boxes are reflected correctly but not dropdown.
What am I missing ? Having issues with binding the data to dropdown within a Grid.

<%@ Register Assembly="obout_ComboBox" Namespace="Obout.ComboBox" TagPrefix="cc2" %>
<%@ Register Assembly="obout_Grid_NET" Namespace="Obout.Grid" TagPrefix="cc1" %>
  <div class="col-md-12 col-sm-12 col-xs-12">
  <div class="x_panel">               
  <div class="x_content">
   <div>
   <cc1:Grid ID="Grid1" runat="server" AllowAddingRecords="true" CallbackMode="true" Serialize="true" 
                     EnableRecordHover="true" FolderStyle="Styles/style_13" AllowPaging="false" 
                     AllowPageSizeSelection="false"  AutoGenerateColumns="false" 
                     Width= "100%" OnInsertCommand="InsertRecord" 
                     OnDeleteCommand="DeleteRecord" OnUpdateCommand="UpdateRecord"  > 
                     <ClientSideEvents OnClientCallbackError="onCallbackError" />
                   
       <Columns>       
       <cc1:Column HeaderText="ASNNumber" DataField="ReturnASNKey" Visible="false"                     ReadOnly="true" Width="30" ></cc1:Column>
        <cc1:Column  HeaderText="LineNo" DataField="RLineNo" Width="45" ReadOnly="true" > </cc1:Column> 
         <cc1:Column  HeaderText="Bu" DataField="Bu"   Width="150">
          <TemplateSettings TemplateId="BuTemplate"  EditTemplateId="BuTemplate" />
            </cc1:Column>
          //More Columns Present
     </Columns>
      <Templates>
    <cc1:GridTemplate runat="server" ID="BuTemplate" ControlID="ddBu" >
     <Template>
         <asp:DropDownList ID="ddBu" runat="server"   >
          <asp:ListItem Text="CS" Value="CS"></asp:ListItem>
          <asp:ListItem Text="CT" Value="CT"></asp:ListItem>
          <asp:ListItem Text="DS" Value="DS"></asp:ListItem>
          </asp:DropDownList>
            </Template>
             </cc1:GridTemplate>    
          </Templates>         
        </cc1:Grid>
        </div>
        </div>
        </div>
         </div>

   protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
               //other unrelated function calls
            }
             populateInbound_detail();
        }
 protected void InsertRecord(object sender, GridRecordEventArgs e)
        {
// code to update the values in database
 populateInbound_detail();
            }

 private void populateInbound_detail()
        {
            DataTable table = new DataTable();

            // get the connection
            connection.Open();

            // write the sql statement to execute

            string sql = "SELECT * FROM [T1] where ReturnASNKey = '" + txtReturnASNKey.Text + "'   order by RLineNo ASC ";

            // instantiate the command object to fire

            using (SqlCommand cmd = new SqlCommand(sql, connection))
            {
                // get the adapter object and attach the command object to i
                using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
                {
                    ad.Fill(table);
                }

            }
            connection.Close();
            // specify the data source for the GridView
            Grid1.DataSource = table;
            // bind the data now
            Grid1.DataBind();
                }

Answers:

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Method 1

Was able to get it working . My error was
<TemplateSettings TemplateId="BuTemplate" EditTemplateId="BuTemplate" />

It should be
<TemplateSettings EditTemplateId="BuTemplate" />
The addition of TemplateID does not allow to display the stored value on the screen.

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