private void SetClass() { string Cgrade = DDLgrade.SelectedValue; if (string.IsNullOrEmpty(Cgrade)) { BtnRegister.Enabled = false; labelmsg.Text = "暂停注册"; } else { int Rgrade = Int32.Parse(Cgrade); LearnSite.BLL.Room rm = new LearnSite.BLL.Room(); DDLclass.DataSource = rm.GetRegClass(Rgrade); DDLclass.DataTextField = "Rclass"; DDLclass.DataValueField = "Rclass"; DDLclass.DataBind(); labelmsg.Text = ""; } }