protected void btnClassNoPaySta_Click(object sender, EventArgs e) { // 获得班级未缴纳费用统计情况 if (ddlClass.SelectedValue != "null") { // 调用逻辑查询统计情况 gv.DataSource = finSrv.GetClassNoPay(ddlClass.SelectedItem.Text); gv.DataBind(); lbMessage.Text = ""; } else { lbMessage.Text = "请选择班级"; } }