一、非泛型方式,继承自CollectionBase
public class MyClass
{
public static void Main()
{
StringCollection myStringCol = new StringCollection();
myStringCol.Add("a");
myStringCol.Add("b");
Console.Write(myStringCol[0]);
foreach (string myAnimal in myStringCol)
{
Console.Write(myAnimal);
}
Console.ReadKey();
}
}
//自定义集合类
public class StringCollection : CollectionBase
{
public void Add(string newAnimal)
{
List.Add(newAnimal);
}
public void Remove(string newAnimal)
{
List.Remove(newAnimal);
}
public StringCollection() { }
public string this[int animalIndex]
{
get { return (string)List[animalIndex]; }
set { List[animalIndex] = value; }
}
}
二、泛型方式,继承自Collection<T>
下面的代码示例演示如何从构造类型的派生集合类Collection<T>泛型类,以及如何重写受保护InsertItem, RemoveItem, ClearItems,和SetItem方法,以提供自定义行为Add, Insert, Remove,和Clear方法,并设置Item[Int32]属性。
此示例中提供的自定义行为是Changed每个受保护方法结束时引发的通知事件。
Dinosaurs类继承Collection<string>,并定义Changed事件,使用DinosaursChangedEventArgs类用于事件信息和使用枚举标识的更改种类。
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
public class Dinosaurs : Collection<string>
{
public event EventHandler<DinosaursChangedEventArgs> Changed;
protected override void InsertItem(int index, string newItem)
{
base.InsertItem(index, newItem);
EventHandler<DinosaursChangedEventArgs> temp = Changed;
if (temp != null)
{
temp(this, new DinosaursChangedEventArgs(
ChangeType.Added, newItem, null));
}
}
protected override void SetItem(int index, string newItem)
{
string replaced = Items[index];
base.SetItem(index, newItem);
EventHandler<DinosaursChangedEventArgs> temp = Changed;
if (temp != null)
{
temp(this, new DinosaursChangedEventArgs(
ChangeType.Replaced, replaced, newItem));
}
}
protected override void RemoveItem(int index)
{
string removedItem = Items[index];
base.RemoveItem(index);
EventHandler<DinosaursChangedEventArgs> temp = Changed;
if (temp != null)
{
temp(this, new DinosaursChangedEventArgs(
ChangeType.Removed, removedItem, null));
}
}
protected override void ClearItems()
{
base.ClearItems();
EventHandler<DinosaursChangedEventArgs> temp = Changed;
if (temp != null)
{
temp(this, new DinosaursChangedEventArgs(
ChangeType.Cleared, null, null));
}
}
}
// Event argument for the Changed event.
//
public class DinosaursChangedEventArgs : EventArgs
{
public readonly string ChangedItem;
public readonly ChangeType ChangeType;
public readonly string ReplacedWith;
public DinosaursChangedEventArgs(ChangeType change, string item,
string replacement)
{
ChangeType = change;
ChangedItem = item;
ReplacedWith = replacement;
}
}
public enum ChangeType
{
Added,
Removed,
Replaced,
Cleared
};
public class Demo
{
public static void Main()
{
Dinosaurs dinosaurs = new Dinosaurs();
dinosaurs.Changed += ChangedHandler;
dinosaurs.Add("Psitticosaurus");
dinosaurs.Add("Caudipteryx");
dinosaurs.Add("Compsognathus");
dinosaurs.Add("Muttaburrasaurus");
Display(dinosaurs);
Console.WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}",
dinosaurs.IndexOf("Muttaburrasaurus"));
Console.WriteLine("\nContains(\"Caudipteryx\"): {0}",
dinosaurs.Contains("Caudipteryx"));
Console.WriteLine("\nInsert(2, \"Nanotyrannus\")");
dinosaurs.Insert(2, "Nanotyrannus");
Console.WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);
Console.WriteLine("\ndinosaurs[2] = \"Microraptor\"");
dinosaurs[2] = "Microraptor";
Console.WriteLine("\nRemove(\"Microraptor\")");
dinosaurs.Remove("Microraptor");
Console.WriteLine("\nRemoveAt(0)");
dinosaurs.RemoveAt(0);
Display(dinosaurs);
}
private static void Display(Collection<string> cs)
{
Console.WriteLine();
foreach( string item in cs )
{
Console.WriteLine(item);
}
}
private static void ChangedHandler(object source,
DinosaursChangedEventArgs e)
{
if (e.ChangeType==ChangeType.Replaced)
{
Console.WriteLine("{0} was replaced with {1}", e.ChangedItem,
e.ReplacedWith);
}
else if(e.ChangeType==ChangeType.Cleared)
{
Console.WriteLine("The dinosaur list was cleared.");
}
else
{
Console.WriteLine("{0} was {1}.", e.ChangedItem, e.ChangeType);
}
}
}
到此这篇关于C#集合之自定义集合类的文章就介绍到这了。希望对大家的学习有所帮助,也希望大家多多支持编程网。