Entity Framework 学习第二天 续

 1         /// <summary>
 2         /// 根据删除条件进行删除
 3         /// </summary>
 4         /// <param name="removeWhere"></param>
 5         public void remove(System.Linq.Expressions.Expression<Func<StudentInfo, bool>> removeWhere)
 6         {
 7             //使用查找方式，现将要删除的条件传递进来，将要删除的数据查询出来
 8             List<StudentInfo> studentList = db.Student.Where(removeWhere).ToList();
 9             //遍历查询出来的数据，然后进行删除操作，这里用到lambda表达式，后期有时间会写一下有关的使用
10             studentList.ForEach(s => db.Student.Remove(s));
11             db.SaveChanges();
12         }
13         /// <summary>
14         /// 修改数据
15         /// </summary>
16         /// <param name="student"></param>
17         /// <param name="strs">可变参数，传递那些属性被修改了</param>
18         public void update(StudentInfo student,params string[] strs)
19         {
20             DbEntityEntry entry= db.Entry<StudentInfo>(student);
21             entry.State = System.Data.EntityState.Unchanged;
22             //遍历属性，修改其标志位
23             foreach (string temp in strs)
24             {
25                 entry.Property(temp).IsModified = true;
26             }
27             db.SaveChanges();
28         }
29 
30         /// <summary>
31         /// 基本查询
32         /// </summary>
33         /// <param name="where"></param>
34         /// <returns></returns>
35         public List<StudentInfo> where(System.Linq.Expressions.Expression<Func<StudentInfo,bool>> where)
36         {
37            return db.Student.Where(where).ToList();
38         }
39         /// <summary>
40         /// 带排序条件的查询，并包括页数，页容量
41         /// </summary>
42         /// <typeparam name="TKey"></typeparam>
43         /// <param name="where"></param>
44         /// <param name="orderBy"></param>
45         /// <param name="pageSize"></param>
46         /// <param name="pageIndex"></param>
47         /// <returns></returns>
48         public List<StudentInfo> whereByOrder<TKey>(Expression<Func<StudentInfo, bool>> where, Expression<Func<StudentInfo, TKey>> orderBy, int pageSize, int pageIndex)
49         {
50             return db.Student.Where(where).OrderBy(orderBy).Skip(pageIndex - 1).Take(pageSize).ToList();
51         }