<pre name="code" class="csharp"> //EF查询public userinfo GetUser(string username){using (MyShopDBEntities1 entity = new MyShopDBEntities1()){userinfo  user = entity.userinfo.SingleOrDefault(model => model.username == username);return user;}}//修改public userinfo Update(string username,string userpwd){using (MyShopDBEntities1 entity = new MyShopDBEntities1()){// userinfo user = entity.userinfo.SingleOrDefault(model => model.username == username);userinfo user = entity.userinfo.FirstOrDefault(model => model.username == username);if (user != null) {   user.userpassword=userpwd;entity.SaveChanges(); }return user; } }//添加public userinfo Add(userinfo user){using (MyShopDBEntities1 entity = new MyShopDBEntities1()){entity.userinfo.Add(new userinfo(){username = user.username,userpwd = user.userpwd});if (entity.SaveChanges() > 0){return user;}elsereturn null;}}//删除public void Deleted(string  username){using (MyShopDBEntities1 entity = new MyShopDBEntities1()){userinfo user = entity.userinfo.FirstOrDefault(m => m.username == username);if (user != null){entity.userinfo.Remove(user);}if (entity.SaveChanges() > 0){//return 0;}}}

方法二：

 EF4.0和EF5.0增删改查的写法区别及执行Sql的方法EF4.0和EF5.0增删改查的写法区别
public T AddEntity(T entity)
{//EF4.0的写法  添加实体//db.CreateObjectSet<T>().AddObject(entity);//EF5.0的写法db.Entry<T>(entity).State = EntityState.Added;//下面的写法统一db.SaveChanges();return entity;
}
public bool UpdateEntity(T entity)
{//EF4.0的写法//db.CreateObjectSet<T>().Addach(entity);//db.ObjectStateManager.ChangeObjectState(entity, EntityState.Modified);//EF5.0的写法 db.Set<T>().Attach(entity); db.Entry<T>(entity).State = EntityState.Modified; return db.SaveChanges() > 0;
}
public bool DeleteEntity(T entity)
{//EF4.0的写法 //db.CreateObjectSet<T>().Addach(entity);//db.ObjectStateManager.ChangeObjectState(entity, EntityState.Deleted);//EF5.0的写法db.Set<T>().Attach(entity);db.Entry<T>(entity).State = EntityState.Deleted;return db.SaveChanges() > 0;
}public IQueryable<T> LoadEntities(Func<T, bool> whereLambda)
{//EF4.0的写法//return db.CreateObjectSet<T>().Where<T>(whereLambda).AsQueryable();//EF5.0的写法return db.Set<T>().Where<T>(whereLambda).AsQueryable();
}
执行SQL语句
//EF4.0的写法
//int ExcuteSql(string strSql, ObjectParameter[] parameters);
return EFContextFactory.GetCurrentDbContext().ExecuteFunction(strSql, parameters);
//EF5.0的写法int ExcuteSql(string strSql, DbParameter[] parameters);
return DEFContextFactory.GetCurrentDbContext().ExecuteSqlCommand(strSql, parameters);