dropdownlist 二级联动

 protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { GradeBind(); } } //绑定年级 private void GradeBind() { Rubric.BLL.Grades myBll = new Rubric.BLL.Grades(); ddlGrade.DataSource = myBll.GetAllList(); ddlGrade.DataTextField = "Name"; ddlGrade.DataValueField = "GradeId"; ddlGrade.DataBind(); } //ddlGrade的selectindexchanged事件 protected void ddlGrade_SelectedIndexChanged(object sender, EventArgs e) { string _gradeId = ddlGrade.SelectedValue.ToString(); string _str = "GradeId='" + _gradeId + "'"; Rubric.BLL.Courses myBll = new Rubric.BLL.Courses(); DataSet ds = myBll.GetList(_str); ddlCourse.DataSource = ds; ddlCourse.DataTextField = "Name"; ddlCourse.DataValueField = "CourseId"; ddlCourse.DataBind(); }