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);
}
}
