最近在寫學校的SRTP項目--學生信息管理系統，其中涉及到對以下信息的數據庫操作。當然持久化之前要對數據的合法性進行驗證，如果非法要提示合理信息，如果有其他問題會拋出異常。
這些信息幾乎按種來分類，每類一個數據表，也就是一類實體，除了各個實體屬性不同其余操作就相差不大了。那麼怎樣來對這些信息進行統一的操作呢？這裡就用到了多態。下面就用我的實現來作為例子吧，如果大家有什麼好的想法可以提出來，不對的地方希望大家指出。謝謝，呵呵！
涉及到信息：
1.基本信息：學號，姓名，班級，專業，年齡，身份證號，籍貫等
2.家庭信息：家庭住址，家庭電話，家庭成員信息等
3.獎學金信息：包括獲得獎學金的數額，時間，項目等
4.活動信息：參加的活動，活動舉行的時間，活動的結果等
5.資助信息：資助的項目，資助金額，資助時間等
6.處分信息：處分的時間，原因，是否被撤銷等
7.素質測評信息：包括測評的時間，文體，時間等的得分情況
8.參加的比賽信息：包括比賽名稱，時間，結果等
實現概括：
每類信息的添加，修改都有一個專門的VIEW，也就是一個WinForm，他們共同繼承Form_base，base處理共同問題，具體問題子類各自處理
Code
1using System;
2using System.Collections.Generic;
3using System.ComponentModel;
4using System.Data;
5using System.Drawing;
6using System.Linq;
7using System.Text;
8using System.Windows.Forms;
9
10using StudentManagerV3.DataBase;
11
12namespace StudentManagerV3
13{
14 public partial class Form_Base : Form
15 {
16 private StudentManagerDataContext context;
17 private bool isEidt = false;
18 /**//// <summary>
19 /// 視圖的引用，當模型發生改變時更新視圖，呈獻給用戶新結果
20 /// </summary>
21 protected DataGridView GridView { get; set; }
22
23 /**//// <summary>
24 /// 如果是編輯信息，實體不為空，強制轉換成用戶需要的實體
25 /// </summary>
26 protected object Entity { get; set; }
27
28 /**//// <summary>
29 /// 每個Form都單獨維護自己的一個Context，防止產生沖突或者引發錯誤
30 /// </summary>
31 protected StudentManagerDataContext Context
32 {
33 get
34 {
35 if (context == null) throw new ArgumentNullException();
36 return context;
37 }
38 }
39
40 /**//// <summary>
41 /// 標識是編輯信息還是添加新信息，
42 /// </summary>
43 protected bool IsEdit { get { return isEidt; } }
44
45 public Form_Base()
46 { }
47
48 public Form_Base(object entity)
49 {
50 if (entity != null) { isEidt = true; this.Entity = entity; }
51 //AppInfo包含了系統的配置信息
52 context = new StudentManagerDataContext(AppInfo.ConnectionString);
53 }
54
55 //判斷當前操作的實體是否有效
56 protected bool ISLegal()
57 {
58 //全局信息，標識當前實體
59 return DataPool.StudentNumber != "0";
60 }
61
62 public void ShowHandleEntityError(string message)
63 {
64 if (message != null)
65 SMSApplication.WriteLogAndShowSuggestiveInfo(message,
66 SysConfig.Document.SelectNodes(XmlSelectorInfo.ApplicationError)[0].InnerText);
67 else SMSApplication.WriteLogAndShowSuggestiveInfo(message,
68 SysConfig.Document.SelectNodes(XmlSelectorInfo.EntityError)[0].InnerText);
69 }
70
71 /**//// <summary>
72 /// 添加，修改學生信息（除基本信息）的邏輯,統一處理（多態的實現）
73 /// </summary>
74 protected void AddOrEditInfo()
75 {
76 try
77 {
78 if (ISLegal())
79 {
80 ConstructEntityInfo();
81 SMSApplication.ShowOperateSucceedResult();
82 }
83 else ShowHandleEntityError(null); ;
84 }
85 catch (FormatException exp)
86 {
87 //SMSApplication系統寫入日志和顯示友好信息的組件，XmlSelectorInfo記錄xml配置文件尋址信息
88 SMSApplication.WriteLogAndShowSuggestiveInfo(exp.Message, SysConfig.Document.SelectNodes(XmlSelectorInfo.FormatError)[0].InnerText);
89 }
90 catch (OverflowException exo)
91 {
92 SMSApplication.WriteLogAndShowSuggestiveInfo(exo.Message, SysConfig.Document.SelectNodes(XmlSelectorInfo.OverFlowError)[0].InnerText);
93 }
94 catch (Exception ex)
95 {
96 ShowHandleEntityError(ex.Message);
97 }
98 this.Dispose();
99 }
100 /**//// <summary>
101 /// 獲得新信息實體的方法，由子類實現
102 /// </summary>
103 protected virtual void ConstructEntityInfo()
104 {
105 throw new NotImplementedException();
106 }
107
108 }
109}
110
其中幾個子類的實現：
Code
1using System;
2using System.Collections.Generic;
3using System.ComponentModel;
4using System.Data;
5using System.Drawing;
6using System.Linq;
7using System.Text;
8using System.Windows.Forms;
9
10using StudentManagerV3.DataBase;
11
12namespace StudentManagerV3
13{
14 public partial class Form_Game : Form_Base
15 {
16 /**//// <summary>
17 /// 修改添加時對應的實體
18 /// </summary>
19 private Game game = new Game();
20
21 public Form_Game(DataGridView view, object entity)
22 : base(entity)
23 {
24 //這個通過Base放到父類中更合適，這樣每個子類又減少了代碼量，放到這裡也算是錯誤代碼的樣例介紹把。呵呵
25 this.GridView = view;
26 this.Entity = entity;
27
28 InitializeComponent();
29
30 //如果是編輯，自然要初始化控件內容
31 if (IsEdit)
32 {
33 game = entity as Game;
34 dateTimePicker_GameTime.Text = game.GameDateTime.ToString();
35 textBox_GameName.Text = game.GameName;
36 textBox_GameResult.Text = game.GameResult;
37 }
38 }
39
40 private void button_AddGame_Click(object sender, EventArgs e)
41 {
42 //調用父類的邏輯
43 AddOrEditInfo();
44 }
45 /**//// <summary>
46 /// 實現父類的方法
47 /// </summary>
48 protected override void ConstructEntityInfo()
49 {
50 if (IsEdit)
51 game = (from ga in Context.Games where ga.GameID == ((Game)Entity).GameID select ga).Single();
52 game.GameResult = textBox_GameResult.Text;
53 game.GameName = textBox_GameName.Text;
54 game.GameDateTime = Convert.ToDateTime(dateTimePicker_GameTime.Text);
55 if (!IsEdit)
56 {
57 game.StudentNumber = DataPool.StudentNumber;
58 Context.Games.InsertOnSubmit(game);
59 }
60 Context.SubmitChanges();
61 GridView.DataSource = GetIQueryable.GetGameQueryable(Context);
62 }
63
64 private void button_CancleGame_Click(object sender, EventArgs e)
65 {
66 this.Dispose();
67 }
68 }
69}
70
Code
1using System;
2using System.Linq;
3using System.Windows.Forms;
4
5using StudentManagerV3.DataBase;
6
7namespace StudentManagerV3
8{
9 /**//// <summary>
10 /// 注釋沒寫，同上一個類差不多
11 /// </summary>
12 public partial class Form_Support : Form_Base
13 {
14 private StudentSupport support = new StudentSupport();
15
16 public Form_Support(DataGridView gridview, object entity)
17 : base(entity)
18 {
19 this.GridView = gridview;
20 this.Entity = entity;
21 InitializeComponent();
22 if (IsEdit)
23 {
24 support = entity as StudentSupport;
25 dateTimePicker_SupportTime.Text = support.SupportTime.ToShortDateString();
26 textBox_SupportAmount.Text = support.SupportAmount.ToString();
27 textBox_SupportRemark.Text = support.SupportRemark;
28 textBox_SupportSource.Text = support.SupportFrom;
29 }
30 }
31
32 private void button_AddSupport_Click(object sender, EventArgs e)
33 {
34 AddOrEditInfo();
35 }
36
37 protected override void ConstructEntityInfo()
38 {
39 if (IsEdit)
40 support = (from su in Context.StudentSupports where su.SupportID == ((StudentSupport)Entity).SupportID select su).Single();
41 support.SupportAmount = Convert.ToInt32(textBox_SupportAmount.Text);
42 support.SupportFrom = textBox_SupportSource.Text;
43 support.SupportRemark = textBox_SupportRemark.Text;
44 support.SupportTime = Convert.ToDateTime(dateTimePicker_SupportTime.Text);
45 if (!IsEdit)
46 {
47 support.StudentNumber = DataPool.StudentNumber;
48 Context.StudentSupports.InsertOnSubmit(support);
49 }
50 Context.SubmitChanges();
51 GridView.DataSource = GetIQueryable.GetSupportQueryable(Context);
52 }
53
54 private void button_CancleSupport_Click(object sender, EventArgs e)
55 {
56 this.Dispose();
57 }
58 }
59}
60
多態的實現基本就是子類中調用AddOrEditInfo()的過程了。呵呵 ，就到這裡拉
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