判断是否重复录入

 Dqt.Reporter.Model.user UserModel = new Dqt.Reporter.Model.user();        List<Dqt.Reporter.Model.user> userlist = UserBLL.GetModelList("UserName='" + this.TxtUserName.Text.Trim() + "'");        if (userlist.Count > 0)        {            Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "", "alert('请勿重复录入!');", true);            return;        }