static void Main(string[] args)
{
//创建修改的对象
Users change = new Users()
{
UNum = 10000,
UName = "admin",
UPass = "******"
};
using (EFDemoEntities db = new EFDemoEntities())
{
//将对象加入EF容器
DbEntityEntry entity = db.Entry <Users>(change);
//设置对象状态
entity.State = System.Data.EntityState.Unchanged;
//Modified状态 设置被修改的列
entity.Property("UNum").IsModified = false;
entity.Property("UName").IsModified = true;
entity.Property("UPass").IsModified = true;
//保存修改
db.SaveChanges();
Console.WriteLine("数据修改成功！");
}
}
/// <summary>
/// 返回根据Lambda表达式排序后的用户表
/// </summary>
/// <typeparam name="TKey">排序字段类型</typeparam>
/// <param name="where">数据查询条件</param>
/// <param name="lambda">数据排序条件</param>
/// <returns></returns>
private static List <Users> GetListByOrder <TKey>(Expression <Func <Users, bool> > where,
Expression <Func <Users, TKey> > lambda)
{
using (EFDemoEntities db = new EFDemoEntities())
{
return(db.Users.Where(where).OrderBy(lambda).ToList());
}
}
/// <summary>
/// 分页查询
/// </summary>
/// <typeparam name="Tkey">排序列的数据类型</typeparam>
/// <param name="pageIndex">当前页索引</param>
/// <param name="pageSize">每页显示的数量</param>
/// <param name="where">查询范围表达式</param>
/// <param name="order">排序表达式</param>
/// <returns></returns>
private static List <Users> GetPage <Tkey>(int pageIndex, int pageSize,
Expression <Func <Users, bool> > where,
Expression <Func <Users, Tkey> > order)
{
using (EFDemoEntities db = new EFDemoEntities())
{
return(db.Users.Where(where).OrderBy(order).Skip(pageIndex * pageSize).Take(pageSize).ToList());
}
}
static void Main(string[] args)
{
using (EFDemoEntities db = new EFDemoEntities())
{
DbQuery <Users> query = db.Users.Where(u => u.UName == "admin") as DbQuery <Users>;
Users admin = query.FirstOrDefault();
Console.WriteLine("\t 编号 \t 账户 \t 密码");
Console.WriteLine("\t {0} \t {1} \t {2}", admin.UNum, admin.UName, admin.UPass);
}
}
static void Main(string[] args)
{
using (EFDemoEntities db = new EFDemoEntities())
{
//创建需要删除的对象
Users del = new Users()
{
UNum = 10001
};
//附加到EF中
db.Users.Attach(del);
//标记为删除
db.Users.Remove(del);
//提交修改
db.SaveChanges();
Console.WriteLine("数据删除成功！");
}
}
static void Main(string[] args)
{
using (EFDemoEntities db = new EFDemoEntities())
{
//循环添加50个账户
for (int i = 0; i < 50; i++)
{
Users u = new Users()
{
UName = "Test" + i,
UPass = "******" + i,
};
db.Users.Add(u);
}
//保存更改
//批处理 多次添加 一次实现
db.SaveChanges();
Console.WriteLine("数据添加成功！");
}
}
