asp.net动态生成select下拉列表内容

<select id="dlOrg" name="D1" runat=server>                            <option></option>                        </select><asp:SqlDataSource ID="SqlDataSource2" runat="server"                             ConnectionString="<%$ ConnectionStrings:wzjrConnectionString %>"                             SelectCommand="SELECT [机构代码], [机构名称] FROM [基础机构代码] where 机构类别='B'"></asp:SqlDataSource>

protected void Page_Load(object sender, EventArgs e)        {            if (!Page.IsPostBack)            {                dlOrg.DataSourceID = "SqlDataSource2";                dlOrg.DataTextField = "机构名称";                dlOrg.DataValueField = "机构代码";            }}