asp.net中DropDownList添加“請選擇”提示

protected void page_load(object sender, eventargs e)

        {

            if (!ispostback)

            {

                bind();

            }

          this.drpdowndepartment.items.insert(0, new listitem("請選擇部門", "0"));

        }

在調用的時候，需要做一個判斷:

            if (this.drpdowndepartment.selecteditem.text != "請選擇部門......")

                staffbll.updatestaffdepidbyid(this.lblnum.text, departmentid);