//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"