GridView和下拉菜单DropDownList结合

后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class Default4 : System.Web.UI.Page
{
    SqlConnection sqlcon;
    string strCon = "Data Source=(local);Database=北风贸易;Uid=sa;Pwd=sa";
    protected void Page_Load(object sender, EventArgs e)
    {
        DropDownList ddl;
        if (!IsPostBack)
        {
            string sqlstr = "select top 5 * from 飞狐工作室";
            sqlcon = new SqlConnection(strCon);
            SqlDataAdapter myda = new SqlDataAdapter(sqlstr, sqlcon);
            DataSet myds = new DataSet();
            sqlcon.Open();
            myda.Fill(myds, "飞狐工作室");
            GridView1.DataSource = myds;
            GridView1.DataBind();
            for (int i = 0; i <= GridView1.Rows.Count - 1; i++)
            {
                DataRowView mydrv = myds.Tables["飞狐工作室"].DefaultView[i];
                if (Convert.ToString(mydrv["员工性别"]).Trim() == "True")
                {
                    ddl = (DropDownList)GridView1.Rows[i].FindControl("DropDownList1");
                    ddl.SelectedIndex = 0;
                }
                if (Convert.ToString(mydrv["员工性别"]).Trim() == "False")
                {
                    ddl = (DropDownList)GridView1.Rows[i].FindControl("DropDownList1");
                    ddl.SelectedIndex = 1;
                }
            }
            sqlcon.Close();
        }
    }

//QQ:272912705 光之翼 www.hi.baidu.com/jcomet
    public SqlDataReader ddlbind()
    {
        string sqlstr = "select distinct 员工性别 from 飞狐工作室";
        sqlcon = new SqlConnection(strCon);
        SqlCommand sqlcom = new SqlCommand(sqlstr, sqlcon);
        sqlcon.Open();
        return sqlcom.ExecuteReader();
    }

前台主要代码：
<asp:GridView ID="GridView1" runat="server" AllowSorting="True" AutoGenerateColumns="False"
                        CellPadding="3" Font-Size="9pt" BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px">
                        <FooterStyle BackColor="White" ForeColor="#000066" />
                        <Columns>
                             <asp:BoundField DataField="身份证号码" HeaderText="用户ID" SortExpression="身份证号码" />
                            <asp:BoundField DataField="姓名" HeaderText="用户姓名" SortExpression="姓名"/>
                            <asp:TemplateField HeaderText="员工性别">
                                <ItemTemplate>
                                    <asp:DropDownList ID="DropDownList1" runat="server" DataSource='<%# ddlbind()%>' DataValueField="员工性别" DataTextField="员工性别">
                                    </asp:DropDownList>
                                </ItemTemplate>
                            </asp:TemplateField>
                            <asp:BoundField DataField="家庭住址" HeaderText="家庭住址" SortExpression="家庭住址"/>
                              
                        </Columns>
                        <RowStyle ForeColor="#000066" />
                        <SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
                        <PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
                        <HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
                    </asp:GridView>