下拉框联动

  //下拉框DropDownList1事件（DropDownList1为一级下拉框，ddl_stu为二级下拉框）   protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)    {        string id= DropDownList1.SelectedValue;           ddl_stu.Items.Clear();        ddl_stu.Items.Add("请选择学生");        ddl_stu.Items[0].Value = "0";        //绑定下拉框ddl_stu        DataSet ds = SqlHelper.ExecuteDataSet("select Id,Name from StuInfo where BanJiId =" + id);        ddl_stu.DataSource = ds.Tables[0].DefaultView;        ddl_stu.DataTextField = "Name";        ddl_stu.DataValueField = "Id";        ddl_stu.DataBind();    }

 

注：

父框(DropDownList1)：AutoPostBack="true"

子框(ddl_stu)：AutoPostBack="true"AppendDataBoundItems="True"