How to display the default selectedvalue of a Drodownlist when edit a row in a gridview ?

See more:

C#

ASP.NET

I have a gridview, in which one column has been transoformed to TemplateField that likes this:

<asp:TemplateField HeaderText="name" SortExpression="name">
    <EditItemTemplate>
        <asp:TextBox ID="TextBox_Name" runat="server" Text='<%# Bind("name") %>' </asp:TextBox>
    </EditItemTemplate>
    <ItemTemplate>
        <asp:Label ID="Label_Name" runat="server" Text='<%# Bind("name") %>'></asp:Label>
    </ItemTemplate>
 </asp:TemplateField>
<asp:TemplateField HeaderText="id" SortExpression="id">
    <EditItemTemplate>
        <asp:TextBox ID="TextBox_ID" runat="server" Text='<%# Bind("id") %>' </asp:TextBox>
    </EditItemTemplate>
    <ItemTemplate>
        <asp:Label ID="Label_ID" runat="server" Text='<%# Bind("id") %>'></asp:Label>
    </ItemTemplate>
 </asp:TemplateField>
 <asp:TemplateField HeaderText="sex" SortExpression="sex">
    <ItemTemplate>
         <asp:Label ID="Label_Sex" runat="server" Text='<%# Bind("sex") %>'></asp:Label>
    </ItemTemplate>
    <EditItemTemplate>
         <asp:DropDownList ID="DropDownList_Sex" runat="server" >
             <asp:ListItem>Male</asp:ListItem>
             <asp:ListItem>Female</asp:ListItem>
             </asp:DropDownList>
    </EditItemTemplate>
 </asp:TemplateField>

If I load a record from DB, for example :

ID      Name             Sex                    
098     Mary Loen        Sorry, It is a secret.

When I edit this record in the gridview's updating event, the displayed dropdownlist's selectedvalue is not the record "Sorry, It is a secret.", but the first item - "Male".

The C# code is:

protected void GridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
   DataTable dt = new DataTable();
   dt = (DataTable)Cache["dataTable"];
   dt.PrimaryKey = new DataColumn[] { dt.Columns["id"] };
   DataRow dr = dt.Rows.Find(Session["ID"].ToString());

   TextBox tb = (TextBox)GridView.Rows[e.RowIndex].FindControl("TextBox_Name");
   dr["name"] = tb.Text.Trim();

   drdList = (DropDownList)(GridView.Rows[e.RowIndex].Cells[1].FindControl("DropDownList_Sex"));
   dr["sex"] = drdList.SelectedValue;

   GridView.EditIndex = -1;
   FillData2Grid();
}
	
protected void GridView_RowEditing(object sender, GridViewEditEventArgs e)
{
   GridView.EditIndex = e.NewEditIndex;
   FillData2Grid();
   TextBox tb = (TextBox)GridView.Rows[e.NewEditIndex].FindControl("TextBox_ID");
   Session["ID"] = tb.Text;
}

How could I make the dropdownlist show the original selectedvalue ?