下拉菜单取值

                staff sf = new staff();
                droppeople.DataSource = sf.sel_staff();
                droppeople.DataTextField = "s_name";
                droppeople.DataValueField = "s_id";
                droppeople.DataBind();

        this.treveive.Text = this.droppeople.SelectedItem.Text.ToString();  //取得s_name的值
        ViewState["receiveid"] = this.droppeople.SelectedValue.ToString();  //取得s_id的值