Visual Basic.net ArrayList 用法

ArrayList代表一个动态的，此类实现大小可动态调整的对象数组，提供了一般的集合功能，适合于大多数用户应用。

ArrayList有三个构造器:

1．ArrayList()

　　直接实例化，后调用方法添加或者删除列表条目

Dim pan1 as New ArrayList()

pan1.add(“number1”)

dim arr1 as New Collection

arr1.add(“number2”)

arr1.add(“ss3”)

pan1.addrange(arr1)

2．ArrayList(int32)

给 ArrayList的构造器传递一个整数，以设定 ArrayList的初始容量。

Dim pan1 as ArrayList(5) ‘设定ArrayList初始容量

Dim cc as Collection

cc.add(string1)

cc.add(string2)

pan1.addrange(cc)

pan1.capacity=8    ‘将arraylist容量重新设定为8

MsgBox(pan1.capacity)

‘TrimToSize()方法将arraylist容量压缩成实际的元素数量

‘pan1.capacity 与pan1.trimtosize()及pan1.count等价

pan1.trimtosize()

3.ArrayList(ICollection)

ArrayList的构造器可以接受一个集合

Dim cc As New Collection
cc.add("string1")
cc.Add("string2")
Dim pan1 As New ArrayList(cc)

实例:

Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesArrayList    

    Public Shared Sub Main()

        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("Hello")
        myAL.Add("World")
        myAL.Add("!")

        ' Displays the properties and values of the ArrayList.
        Console.WriteLine("myAL")
        Console.WriteLine("    Count:    {0}", myAL.Count)
        Console.WriteLine("    Capacity: {0}", myAL.Capacity)
        Console.Write("    Values:")
        PrintValues(myAL)
    End Sub

    Public Shared Sub PrintValues(myList As IEnumerable)
        Dim obj As [Object]
        For Each obj In  myList
            Console.Write("   {0}", obj)
        Next obj
        Console.WriteLine()
    End Sub 'PrintValues

End Class