泛型的小例子,C#3.5版

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;

namespace  Comb
{
     public   partial   class  Form1 : Form
    {
         public  Form1()
        {
            InitializeComponent();
        }
         private   void  addSt()
        {
            List < ComboBoxItem < Student >>  list  =   new  List < ComboBoxItem < Student >> ();
            list.Add( new  ComboBoxItem < Student > ( "" ,  null ));
            Student s1  =   new  Student( " 张三 " ,  15 );
            Student s2  =   new  Student( " 李四 " ,  20 );
            list.Add( new  ComboBoxItem < Student > (s1.Name, s1));
            list.Add( new  ComboBoxItem < Student > (s2.Name, s2));
             // 绑定下拉框
            comboBox1.DataSource  =  list;
            comboBox1.DisplayMember  =   " ItemText " ;
            comboBox1.ValueMember  =   " ItemValue " ;
        }

         private   void  comboBox1_SelectedIndexChanged( object  sender, EventArgs e)
        {
             // addSt();
             if  (comboBox1.SelectedIndex  >   0 )
            {
                Student s  =  (Student)comboBox1.SelectedValue;
                MessageBox.Show(s.Age.ToString());
            }
        }

         private   void  button1_Click( object  sender, EventArgs e)
        {
            
        }

         private   void  Form1_Load( object  sender, EventArgs e)
        {
            addSt();
        }

    }

     public   class  ComboBoxItem < T >
    {
         // ItemText显示的文字
        //  private string _itemText;
         public   string  ItemText
        {
             get ; set ;
             // get { return _itemText ; }
             // set { _itemText = value; }
        }
         // ItemValue实际的值
        //  private T _itemValue;
         public  T ItemValue
        {
             get ; set ;
             // get { return _itemValue; }
             // set { _itemValue = value; }
        }
         // 构造方法
         public  ComboBoxItem( string  itemText, T itemValue)
        {
             // this._itemText = itemText;
             // this._itemValue = itemValue;
            ItemText  =  itemText;
            ItemValue  =  itemValue;
        }
         // 自定义方法
         // 确定指定的对象是否等于当前对象
         public   override   bool  Equals( object  obj)
        {
            //  2643993
             if  (obj  is  ComboBoxItem < T > )
            {
                ComboBoxItem < T >  rhs  =  (ComboBoxItem < T > )obj;
                //  if (_itemText.Equals(rhs.ItemText) && _itemValue.Equals(rhs.ItemValue))
                 if (ItemText.Equals(rhs.ItemText) && ItemValue.Equals(rhs.ItemValue))
                     return   true ;
                 else
                     return   false ;
            }
             else
                 return   false ;
        }
         // 获取当前对象的哈希代码
         public   override   int  GetHashCode()
        {
             return  ItemText.GetHashCode()  +  ItemValue.GetHashCode();
        }
         // 重载相等操作符
         public   static   bool   operator   == (ComboBoxItem < T >  lhs, ComboBoxItem < T >  rhs)
        {  return  lhs.Equals(rhs); }
         // 重载不等
         public   static   bool   operator   != (ComboBoxItem < T >  lhs, ComboBoxItem < T >  rhs)
        {  return   ! (lhs.Equals(rhs)); }
    }
     // 学生对象
     public   class  Student
    {
         // 姓名
         private   string  _name;
         public   string  Name
        {  get  {  return  _name; } }
         // 年龄
         private   int  _age;
         public   int  Age
        {  get  {  return  _age; } }
         // 构造方法
         public  Student( string  name,  int  age)
        {
            _name  =  name;
            _age  =  age;
        }
    }
}