Using CustomCollection : IEnumerable « Collections « ASP.NET Tutorial






<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="UsingCustomCollection" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Using a Customer Collection</title>
</head>
<body>
    <form id="form1" runat="server">
   <div id="container">
      <h1>Using a Customer Collection</h1>
      This example illustrates the use of a custom collection
      <asp:DropDownList ID="drpSample" runat="server" 
         DataTextField="Name"
         DataValueField="Id"
/>
      
   </div>
    </form>
</body>
</html>

File: Default.aspx.cs

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class UsingCustomCollection : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
       Customer c1 = new Customer("1", "A", "AA", "123-4567");
       Customer c2 = new Customer("2", "B", "BB", "123-1267");
       Customer c3 = new Customer("3", "C", "CC", "123-7823");
       Customer c4 = new Customer("4", "D", "DD", "123-6383");

       CustomerCollection cc = new CustomerCollection();
       cc.Add(c1);
       cc.Add(c2);
       cc.Add(c3);
       cc.Add(c4);

       drpSample.DataSource = cc;
       drpSample.DataBind();
    }
}

public class CustomerCollection: IEnumerable
{

   private ArrayList _customers;

  public CustomerCollection()
  {
      _customers = new ArrayList();
  }

   public void Add(Customer c)
   {
      if (c != null)
         _customers.Add(c);
   }


   public Customer this[int index]
   {
      get {
         if (index >= 0 && index < _customers.Count)
            return (Customer)_customers[index];
         else
            return null;
      }
   }

   public Customer FindById(string id)
   {
      foreach (Customer c in _customers)
      {
         if (c.Id == id)
            return c;
      }
      return null;
   }

   public IEnumerator GetEnumerator()
   {
      return _customers.GetEnumerator();
   }
}
public abstract class AbstractEntity
{

   private string _id;

  public AbstractEntity(string id)
  {
      _id = id;
  }


   public string Id
   {
      get { return _id; }
      set { _id = value; }
   }


   public abstract bool IsValid
   {
      get;
   }
}

public class Customer: AbstractEntity 
{
   // data members
   private string _firstName;
   private string _lastName;
   private string _phone;

   public Customer(string id, string firstName, string lastName, string phone): base(id)
   {
      _firstName = firstName;
      _lastName = lastName;
      _phone = phone;
   }


   public string FirstName
   {
      get { return _firstName; }
      set { _firstName = value; }
   }
   public string LastName
   {
      get { return _lastName; }
      set { _lastName = value; }
   }
   public string Phone
   {
      get { return _phone; }
      set { _phone = value; }
   }
   public string Name
   {
      get { return LastName + ", " + FirstName; }
   }

   public override bool IsValid
   {
      get
      {
         if (Id.Length > 0 && LastName.Length > 0)
            return true;
         else
            return false;
      }
   }

   public override string ToString()
   {
      return Id + "," + Name + "," + Phone; 
   }
}








7.6.IEnumerable
7.6.1.Using CustomCollection
7.6.2.IEnumerable, IEnumerator
7.6.3.IEnumerable, IEnumerator (VB)