应用实体类EntitySet实现类似的范型功能
在制做项目时我们都会将数据库中的字段名写成一个类,也就是将数据库中的每一张表写成一个类,我们将它称为实体类.EntitySet类能构将类的很多个实例对象封装在Entities属性中,同时可以记录查询记录的总数,对数据库分页很有用;拥有类是List<>范型功能,应用于所有实体类,能减少我们很多代码.
通常我们要为一个实体类定义四个重要的函数,当然这是最少的要求:(假设我们有一个实体类EntitySimple) 下面我们就定义四个和数据库相关联的函数:
EntitySet其实就是一个ArrayList的变形版,有了这个类在读取是就可以将对象entitySimple给Add进去了,当我们要用的时候就可以直接调用了:EntitySet set=SimpleManager.GetAllEntitySimple().Entities;如果直接使用SimpleManager.GetAllEntitySimple().Entities前显式转化:(EntitySimple)SimpleManager.GetAllEntitySimple().Entities.
代码很简单,但能构充当十分重要的角色,对于一个网站来说需要很多个实体类集合,这里我们就可以用这个类来替代集合类.能构减少很多代码,当然你可以用List<EntitySimple>,但是有时需要TotalRecords,就不能直接从中读取,像上一篇文章中就不需要加out int totalRecords了,可以直接存在这个类里,我觉得这个类会比较好用,所以就拿出来和大家分享一下,或许你有更好的,希望批评指正!
通常我们要为一个实体类定义四个重要的函数,当然这是最少的要求:(假设我们有一个实体类EntitySimple) 下面我们就定义四个和数据库相关联的函数:
1
using System;
2
using System.Data;
3
using System.Data.SqlClient;
4
//其中EntitySimple类位于下面的命名空间中.
5
using NexPlus.Entities;
6
7
namespace NexPlus.Data.SqlDataProvider{
8
public class SimpleDataProvider{
9
10
public SimpleDataProvider(){}
11
12
public bool CreateUpdateEntitySimple(EntitySimple entitySimple,DataAction action){
13
//代码
.
14
}
15
16
public EntitySimple GetEntitySimple(int id){
17
//代码
.
18
}
19
20
public bool DeleteEntitySimple(int id){
21
//代码
.
22
}
23
24
public EntitySet GetAllEntitySimple(){
25
//代码
.
26
}
27
}
28
}
从上面可以很容易看到就是SQL的四大守护神:SELECT,UPDATE,DELETE,INSERT;一般创建和更新就差一个Id,都是用实体类封装实例,所以我们把他们写作同一个函数里,用枚举(DataAction action)来区分创建还是更新.今天我们要讨论的就是EntitySet类,我们来看一下它的代码:
2

3

4

5

6

7

8

9

10

11

12

13


14

15

16

17


18

19

20

21


22

23

24

25


26

27

28

1
using System;
2
using System.Collections;
3
4
namespace NexPlus.Entities
5
{
6
public class EntitySet
7
{
8
ArrayList entities = new ArrayList();
9
int totalRecords = 0;
10
/// <summary>
11
/// 实体总纪录数。
12
/// </summary>
13
public int TotalRecords{
14
get{return totalRecords;}
15
set{totalRecords = value;}
16
}
17
/// <summary>
18
/// 实体项列表。
19
/// </summary>
20
public ArrayList Entities{
21
get{return entities;}
22
}
23
/// <summary>
24
/// 实体中是否有项。
25
/// </summary>
26
public bool HasResults{
27
get{
28
if (entities.Count > 0)
29
return true;
30
return false;
31
}
32
}
33
}
34
}

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

EntitySet其实就是一个ArrayList的变形版,有了这个类在读取是就可以将对象entitySimple给Add进去了,当我们要用的时候就可以直接调用了:EntitySet set=SimpleManager.GetAllEntitySimple().Entities;如果直接使用SimpleManager.GetAllEntitySimple().Entities前显式转化:(EntitySimple)SimpleManager.GetAllEntitySimple().Entities.
代码很简单,但能构充当十分重要的角色,对于一个网站来说需要很多个实体类集合,这里我们就可以用这个类来替代集合类.能构减少很多代码,当然你可以用List<EntitySimple>,但是有时需要TotalRecords,就不能直接从中读取,像上一篇文章中就不需要加out int totalRecords了,可以直接存在这个类里,我觉得这个类会比较好用,所以就拿出来和大家分享一下,或许你有更好的,希望批评指正!
【推荐】编程新体验,更懂你的AI,立即体验豆包MarsCode编程助手
【推荐】凌霞软件回馈社区,博客园 & 1Panel & Halo 联合会员上线
【推荐】抖音旗下AI助手豆包,你的智能百科全书,全免费不限次数
【推荐】博客园社区专享云产品让利特惠,阿里云新客6.5折上折
【推荐】轻量又高性能的 SSH 工具 IShell:AI 加持,快人一步