protected void Button2_Click(object sender, EventArgs e) { // Func<UserInfo, bool> whereLambda = u => { return u.ID == 343; }; EFFristModelEntities db = new EFFristModelEntities(); // var userInfoList = db.UserInfo.Where<UserInfo>(u=>u.ID==3); //select * from UserInfo where id=343 //升序排序 // var userInfoList = db.UserInfo.Where<UserInfo>(U => true).OrderBy<UserInfo, int>(u => u.ID); //降序排序 //var userInfoList = db.UserInfo.Where<UserInfo>(U => true).OrderByDescending(u => u.ID); int pageIndex = 2; int pageSize = 2; var userInfoList = (from u in db.UserInfo where u.ID > 0 orderby u.RegTime ascending, u.ID descending select u).Skip <UserInfo>((pageIndex - 1) * pageSize).Take <UserInfo>(pageSize); // var userInfoList = db.UserInfo.Where<UserInfo>(U => true).OrderByDescending(u => u.UserPass).ThenByDescending<UserInfo, int>(u => u.ID);//Skip:表示跳过多少条记录, Take取多少条记录 foreach (var userInfo in userInfoList) { Response.Write(userInfo.UserName + "<br/>"); } }
protected void Button3_Click(object sender, EventArgs e) { EFFristModelEntities db = new EFFristModelEntities(); //var userInfoList = from u in db.UserInfo // where u.ID == 345 // select u; //UserInfo userInfo=userInfoList.FirstOrDefault();//返回第一个元素,如果没有的话,返回null //if (userInfo != null) //{ // // db.UserInfo.Remove(userInfo); // db.Entry<UserInfo>(userInfo).State = System.Data.EntityState.Deleted; // db.SaveChanges(); //} //else //{ // Response.Write("要删除的数据不存在!!"); //} UserInfo userInfo = new UserInfo() { ID = 344 }; //db.UserInfo.Remove(userInfo); db.Entry <UserInfo>(userInfo).State = System.Data.EntityState.Deleted; db.SaveChanges(); }
protected void Button4_Click(object sender, EventArgs e) { EFFristModelEntities db = new EFFristModelEntities(); var userInfoList = db.UserInfo.Where <UserInfo>(u => u.ID > 0); int i = 0; int count = userInfoList.Count(); Response.Write(count); }
protected void Button4_Click(object sender, EventArgs e) { EFFristModelEntities db = new EFFristModelEntities(); var userInfoList = from u in db.UserInfo where u.ID == 343 select u; var userInfo = userInfoList.FirstOrDefault(); userInfo.UserPass = "******"; db.Entry <UserInfo>(userInfo).State = System.Data.EntityState.Modified; db.SaveChanges(); }
protected void Button1_Click(object sender, EventArgs e) { UserInfo userInfo = new UserInfo(); userInfo.Email = "*****@*****.**"; userInfo.RegTime = DateTime.Now; userInfo.UserName = "******"; userInfo.UserPass = "******"; EFFristModelEntities db = new EFFristModelEntities(); db.UserInfo.Add(userInfo); //将数据添加到EF并且添加了添加标记。 db.SaveChanges(); //数据才会保存到数据库。,返回受影响的行数。 Response.Write(userInfo.ID); }
/// <summary> /// 查询 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> protected void Button2_Click(object sender, EventArgs e) { EFFristModelEntities db = new EFFristModelEntities(); //linq var userInfoList = from u in db.UserInfo where u.ID == 343 select u; int i = 0; foreach (UserInfo userInfo in userInfoList)//EF 延迟加载机制,数据用到的时候才去数据库中查询。不能用的时候不查询。 { Response.Write(userInfo.UserName); } // select * from UserInfo where ID=343 // from UserInfo // where ID=343 // select * }
protected void Button1_Click(object sender, EventArgs e) { EFFristModelEntities db = null; if (HttpContext.Current.Items["db"] == null) { db = new EFFristModelEntities(); HttpContext.Current.Items["db"] = db; } else { db = HttpContext.Current.Items["db"] as EFFristModelEntities; } var userInfoList = from u in db.UserInfo where u.ID == 343 select new{ UName = u.UserName, UPwd = u.UserPass }; foreach (var userInfo in userInfoList) { Response.Write(userInfo.UName + ":" + userInfo.UPwd); } }