CollectionsUtil 類別

定義

public ref class CollectionsUtil

public class CollectionsUtil

type CollectionsUtil = class

Public Class CollectionsUtil

繼承

Object

CollectionsUtil

範例

以下範例使用兩個集合，一個雜湊表與一個排序列表，來儲存一組城市的人口值。 這些值是透過使用城市名稱作為鍵值從集合中取得的。 城市名稱會用混合大小寫表示，以顯示它們作為不區分大小寫的鍵。

using System;
using System.Collections;
using System.Collections.Specialized;

class TestCollectionsUtils
{
    public static void Main()
    {
        Hashtable population1 = CollectionsUtil.CreateCaseInsensitiveHashtable();

        population1["Trapperville"] = 15;
        population1["Doggerton"] = 230;
        population1["New Hollow"] = 1234;
        population1["McHenry"] = 185;

        // Select cities from the table using mixed case.
        Console.WriteLine("Case insensitive hashtable results:\n");
        Console.WriteLine("{0}'s population is: {1}", "Trapperville", population1["trapperville"]);
        Console.WriteLine("{0}'s population is: {1}", "Doggerton", population1["DOGGERTON"]);
        Console.WriteLine("{0}'s population is: {1}", "New Hollow", population1["New hoLLow"]);
        Console.WriteLine("{0}'s population is: {1}", "McHenry", population1["MchenrY"]);

        SortedList population2 = CollectionsUtil.CreateCaseInsensitiveSortedList();

        foreach (string city in population1.Keys)
        {
           population2.Add(city, population1[city]);
        }

        // Select cities from the sorted list using mixed case.
        Console.WriteLine("\nCase insensitive sorted list results:\n");
        Console.WriteLine("{0}'s population is: {1}", "Trapperville", population2["trapPeRVille"]);
        Console.WriteLine("{0}'s population is: {1}", "Doggerton", population2["dOGGeRtON"]);
        Console.WriteLine("{0}'s population is: {1}", "New Hollow", population2["nEW hOLLOW"]);
        Console.WriteLine("{0}'s population is: {1}", "McHenry", population2["MchEnrY"]);
    }
}

// This program displays the following output to the console
//
// Case insensitive hashtable results:
//
// Trapperville's population is: 15
// Doggerton's population is: 230
// New Hollow's population is: 1234
// McHenry's population is: 185
//
// Case insensitive sorted list results:
//
// Trapperville's population is: 15
// Doggerton's population is: 230
// New Hollow's population is: 1234
// McHenry's population is: 185

Imports System.Collections
Imports System.Collections.Specialized

Class TestCollectionsUtils
    Public Shared Sub Main()
        Dim population1 As Hashtable = CollectionsUtil.CreateCaseInsensitiveHashtable()

        population1("Trapperville") = 15
        population1("Doggerton") = 230
        population1("New Hollow") = 1234
        population1("McHenry") = 185

        ' Select cities from the table using mixed case.
        Console.WriteLine("Case insensitive hashtable results:" + Environment.NewLine)
        Console.WriteLine("{0}'s population is: {1}", "Trapperville", population1("trapperville"))
        Console.WriteLine("{0}'s population is: {1}", "Doggerton", population1("DOGGERTON"))
        Console.WriteLine("{0}'s population is: {1}", "New Hollow", population1("New hoLLow"))
        Console.WriteLine("{0}'s population is: {1}", "McHenry", population1("MchenrY"))

        Dim population2 As SortedList = CollectionsUtil.CreateCaseInsensitiveSortedList()

        For Each city As String In population1.Keys
            population2.Add(city, population1(city))
        Next city

        ' Select cities from the sorted list using mixed case.
        Console.WriteLine(Environment.NewLine + "Case insensitive sorted list results:" + Environment.NewLine)
        Console.WriteLine("{0}'s population is: {1}", "Trapperville", population2("trapPeRVille"))
        Console.WriteLine("{0}'s population is: {1}", "Doggerton", population2("dOGGeRtON"))
        Console.WriteLine("{0}'s population is: {1}", "New Hollow", population2("nEW hOLLOW"))
        Console.WriteLine("{0}'s population is: {1}", "McHenry", population2("MchEnrY"))
    End Sub
End Class

' This program displays the following output to the console
'
' Case insensitive hashtable results:
'
' Trapperville's population is: 15
' Doggerton's population is: 230
' New Hollow's population is: 1234
' McHenry's population is: 185
'
' Case insensitive sorted list results:
'
' Trapperville's population is: 15
' Doggerton's population is: 230
' New Hollow's population is: 1234
' McHenry's population is: 185

備註

這些方法透過雜湊碼提供者與比較器的大小寫不區分實作，產生集合的大小寫不區分實例。 所得的實例可以像該類別的其他實例一樣使用，儘管行為可能不同。

例如，假設將兩個鍵為「hello」和「HELLO」的物件加入雜湊表。 一個大小寫區分的雜湊表會產生兩個不同的條目;而大小寫不區分的雜湊表則會在新增第二個物件時拋出例外。

執行緒安全性

A Hashtable 可以同時支援一名寫手與多位讀者。 為了支援多個寫入者，所有操作都必須透過方法回傳 Synchronized(Hashtable) 的包裝器來完成。

SortedList A 可以同時支援多個讀取器，只要集合不被修改。 若要保證 SortedList的線程安全性，所有作業都必須透過 Synchronized(SortedList) 方法傳回的包裝函式來完成。

透過集合列舉本質上不是一個執行緒安全的程序。 即使集合同步處理，其他線程仍然可以修改集合，這會導致列舉值擲回例外狀況。 若要保證列舉期間的線程安全性，您可以在整個列舉期間鎖定集合，或攔截其他線程所做的變更所產生的例外狀況。

另請參閱

• System.Collections
• 在集合中執行 Culture-Insensitive 字串作業