最近在写学校的SRTP项目--学生信息管理系统，其中涉及到对以下信息的数据库操作。当然持久化之前要对数据的合法性进行验证，如果非法要提示合理信息，如果有其他问题会抛出异常。
这些信息几乎按种来分类，每类一个数据表，也就是一类实体，除了各个实体属性不同其余操作就相差不大了。那么怎样来对这些信息进行统一的操作呢？这里就用到了多态。下面就用我的实现来作为例子吧，如果大家有什么好的想法可以提出来，不对的地方希望大家指出。谢谢，呵呵！
涉及到信息：
1. 基本信息：学号，姓名，班级，专业，年龄，身份证号，籍贯等
2. 家庭信息：家庭住址，家庭电话，家庭成员信息等
3. 奖学金信息：包括获得奖学金的数额，时间，项目等
4. 活动信息：参加的活动，活动举行的时间，活动的结果等
5. 资助信息：资助的项目，资助金额，资助时间等
6. 处分信息：处分的时间，原因，是否被撤销等
7. 素质测评信息：包括测评的时间，文体，时间等的得分情况
8. 参加的比赛信息：包括比赛名称，时间，结果等
实现概括：
每类信息的添加，修改都有一个专门的VIEW，也就是一个WinForm，他们共同继承Form_base，base处理共同问题，具体问题子类各自处理
From_Base实现：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using StudentManagerV3.DataBase;
namespace StudentManagerV3
{
public partial class Form_Base : Form
{
private StudentManagerDataContext context;
private bool isEidt = false;
/**////
/// 视图的引用，当模型发生改变时更新视图，呈献给用户新结果
///
protected DataGridView GridView { get; set; }
/**////
/// 如果是编辑信息，实体不为空，强制转换成用户需要的实体
///
protected object Entity { get; set; }
/**////
/// 每个Form都单独维护自己的一个Context，防止产生冲突或者引发错误
///
protected StudentManagerDataContext Context
{
get
{
if (context == null) throw new ArgumentNullException();
return context;
}
}
/**////
/// 标识是编辑信息还是添加新信息，
///
protected bool IsEdit { get { return isEidt; } }
public Form_Base()
{ }
public Form_Base(object entity)
{
if (entity != null) { isEidt = true; this.Entity = entity; }
//AppInfo包含了系统的配置信息
context = new StudentManagerDataContext(AppInfo.ConnectionString);
}
//判断当前操作的实体是否有效
protected bool ISLegal()
{
//全局信息，标识当前实体
return DataPool.StudentNumber != "0";
}
public void ShowHandleEntityError(string message)
{
if (message != null)
SMSApplication.WriteLogAndShowSuggestiveInfo(message,
SysConfig.Document.SelectNodes(XmlSelectorInfo.ApplicationError)[0].InnerText);
else SMSApplication.WriteLogAndShowSuggestiveInfo(message,
SysConfig.Document.SelectNodes(XmlSelectorInfo.EntityError)[0].InnerText);
}
/**////
/// 添加，修改学生信息（除基本信息）的逻辑,统一处理（多态的实现）
///
protected void AddOrEditInfo()
{
try
{
if (ISLegal())
{
ConstructEntityInfo();
SMSApplication.ShowOperateSucceedResult();
}
else ShowHandleEntityError(null); ;
}
catch (FormatException exp)
{
//SMSApplication系统写入日志和显示友好信息的组件，XmlSelectorInfo记录xml配置文件寻址信息
SMSApplication.WriteLogAndShowSuggestiveInfo(exp.Message, SysConfig.Document.SelectNodes(XmlSelectorInfo.FormatError)[0].InnerText);
}
catch (OverflowException exo)
{
SMSApplication.WriteLogAndShowSuggestiveInfo(exo.Message, SysConfig.Document.SelectNodes(XmlSelectorInfo.OverFlowError)[0].InnerText);
}
catch (Exception ex)
{
ShowHandleEntityError(ex.Message);
}
this.Dispose();
}
/**////
/// 获得新信息实体的方法，由子类实现
///
protected virtual void ConstructEntityInfo()
{
throw new NotImplementedException();
}
}
}
其中几个子类的实现：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using StudentManagerV3.DataBase;
namespace StudentManagerV3
{
public partial class Form_Game : Form_Base
{
/**////
/// 修改添加时对应的实体
///
private Game game = new Game();
public Form_Game(DataGridView view, object entity)
: base(entity)
{
//这个通过Base放到父类中更合适，这样每个子类又减少了代码量，放到这里也算是错误代码的样例介绍把。呵呵
this.GridView = view;
this.Entity = entity;
InitializeComponent();
//如果是编辑，自然要初始化控件内容
if (IsEdit)
{
game = entity as Game;
dateTimePicker_GameTime.Text = game.GameDateTime.ToString();
textBox_GameName.Text = game.GameName;
textBox_GameResult.Text = game.GameResult;
}
}
private void button_AddGame_Click(object sender, EventArgs e)
{
//调用父类的逻辑
AddOrEditInfo();
}
/**////
/// 实现父类的方法
///
protected override void ConstructEntityInfo()
{
if (IsEdit)
game = (from ga in Context.Games where ga.GameID == ((Game)Entity).GameID select ga).Single();
game.GameResult = textBox_GameResult.Text;
game.GameName = textBox_GameName.Text;
game.GameDateTime = Convert.ToDateTime(dateTimePicker_GameTime.Text);
if (!IsEdit)
{
game.StudentNumber = DataPool.StudentNumber;
Context.Games.InsertOnSubmit(game);
}
Context.SubmitChanges();
GridView.DataSource = GetIQueryable.GetGameQueryable(Context);
}
private void button_CancleGame_Click(object sender, EventArgs e)
{
this.Dispose();
}
}
}
using System;
using System.Linq;
using System.Windows.Forms;
using StudentManagerV3.DataBase;
namespace StudentManagerV3
{
/**////
/// 注释没写，同上一个类差不多
///
public partial class Form_Support : Form_Base
{
private StudentSupport support = new StudentSupport();
public Form_Support(DataGridView gridview, object entity)
: base(entity)
{
this.GridView = gridview;
this.Entity = entity;
InitializeComponent();
if (IsEdit)
{
support = entity as StudentSupport;
dateTimePicker_SupportTime.Text = support.SupportTime.ToShortDateString();
textBox_SupportAmount.Text = support.SupportAmount.ToString();
textBox_SupportRemark.Text = support.SupportRemark;
textBox_SupportSource.Text = support.SupportFrom;
}
}
private void button_AddSupport_Click(object sender, EventArgs e)
{
AddOrEditInfo();
}
protected override void ConstructEntityInfo()
{
if (IsEdit)
support = (from su in Context.StudentSupports where su.SupportID == ((StudentSupport)Entity).SupportID select su).Single();
support.SupportAmount = Convert.ToInt32(textBox_SupportAmount.Text);
support.SupportFrom = textBox_SupportSource.Text;
support.SupportRemark = textBox_SupportRemark.Text;
support.SupportTime = Convert.ToDateTime(dateTimePicker_SupportTime.Text);
if (!IsEdit)
{
support.StudentNumber = DataPool.StudentNumber;
Context.StudentSupports.InsertOnSubmit(support);
}
Context.SubmitChanges();
GridView.DataSource = GetIQueryable.GetSupportQueryable(Context);
}
private void button_CancleSupport_Click(object sender, EventArgs e)
{
this.Dispose();
}
}
}
来源：http://www.cnblogs.com/jingtao/archive/2008/04/23/1167006.html