关于集合类的做法！
类工程：
using System;
using System.Data;
namespace MyProduct.Employee
{
/// <summary>
/// Employee的实体类
/// </summary>
public class EmployeeEntity
{
private int mEmployeeID;
private string mLastName;
private string mFirstName;
public int EmployeeID
{
get { return mEmployeeID; }
set { mEmployeeID = value; }
}
public string LastName
{
get { return mLastName; }
set { mLastName = value; }
}
public string FirstName
{
get { return mFirstName; }
set { mFirstName = value; }
}
public EmployeeEntity()
{
}
/// <summary>
/// 构造函数，给实体类赋值
/// </summary>
/// <param name="pDR">DataRow</param>
public EmployeeEntity(DataRow pDR)
{
Fill(pDR);
}
/// <summary>
/// 给实体类赋值
/// </summary>
/// <param name="pDR">DataRow</param>
public void Fill(DataRow pDR)
{
foreach( System.Reflection.PropertyInfo pi in this.GetType().GetProperties())
{
if (pi.CanWrite)
{
try
{
if (pDR[ pi.Name ] != null && !pDR.IsNull( pi.Name ) )
{
pi.Setvalue(this, pDR[ pi.Name ], null);
}
else
{
pi.Setvalue(this, null, null);
}
}
catch
{
pi.Setvalue(this, null, null);
}
}
}
}
}
/// <summary>
/// Employee的集合类
/// </summary>
public class EmployeeList : System.Collections.CollectionBase
{
public EmployeeList()
{
}
/// <summary>
/// 构造函数，给集合类赋值
/// </summary>
/// <param name="pDT">DataTable</param>
public EmployeeList(DataTable pDT)
{
Fill(pDT);
}
/// <summary>
/// 给集合类赋值
/// </summary>
/// <param name="pDT">DataTable</param>
public void Fill(DataTable pDT)
{
foreach(DataRow pDR in pDT.Rows)
{
this.InnerList.Add( new EmployeeEntity( pDR ) );
}
}
/// <summary>
/// 索引
/// </summary>
public virtual EmployeeEntity this[int Index]
{
get
{
return (EmployeeEntity)this.List[Index];
}
}
/// <summary>
/// 添加
/// </summary>
/// <param name="pEmp">实体类</param>
public virtual void Add(EmployeeEntity pEmp)
{
this.List.Add(pEmp);
}
/// <summary>
/// 删除
/// </summary>
/// <param name="Index">index</param>
public virtual void Remove(int Index)
{
this.List.RemoveAt(Index);
}
}
/// <summary>
/// Employee业务类
/// </summary>
public class EmployeeRule
{
/// <summary>
/// 获取所有
/// </summary>
/// <returns></returns>
public EmployeeList GetAllEmployees()
{
string sql;
sql="select * from employees";
DataTable pDT=ExeForDtl(sql);
EmployeeList emplist=new EmployeeList();
emplist.Fill(pDT);
return emplist;
}
/// <summary>
/// 获取一个
/// </summary>
/// <param name="pEmployeeID"></param>
/// <returns></returns>
public EmployeeEntity GetOneEmployee(int pEmployeeID)
{
string sql;
sql="select * from employees where employeeid="+pEmployeeID;
DataTable pDT=new DataTable();
pDT=ExeForDtl(sql);
if(pDT.Rows.Count>0)
{
return new EmployeeEntity(pDT.Rows[0]);
}
else
{
return null;
}
}
}
}
Web工程：
这里的Web工程说明了怎样去调用我们写的集合类。
1。在DataGrid中使用集合类
直接绑定：
EmployeeRule empRule=new EmployeeRule();
DataGrid1.DataSource=empRule.GetAllEmployees();
DataGrid1.DataBind();
手工添加绑定：
EmployeeEntity emp=new EmployeeEntity();
emp.EmployeeID=10;
emp.FirstName="mike";
emp.LastName="daoson";
EmployeeList empList=new EmployeeList();
empList.Add(emp);
DataGrid1.DataSource=empList;
DataGrid1.DataBind();
2。给文本框赋值
EmployeeEntity emp=new EmployeeEntity();
emp=empRule.GetOneEmployee(1);
txtEmployeeID.Text=emp.EmployeeID.ToString();
txtFirstName.Text=emp.FirstName;
txtLastName.Text=emp.LastName;
下面讲一下此种方法的优缺点：
优点：
1。通过反射，循环给属性赋值，省去了给属性赋值的大量工作量
2。集合类可以直接绑定到DataGrid中
3。自己如果想构造一个虚拟的DataTable，可以通过集合类来做
4。这种方法可以用foreach做循环来检索出他的实体类
5。这里可以直接把datarow赋给实体类，也可以给实体类手工赋值
缺点：
1。数据库中的字段名必须要和实体类中的属性相一致
2。如果是多个表关联，那么集合类就不能绑定到DataGrid