C# |获取遍历 SortedList 的枚举器

原文:https://www . geeksforgeeks . org/c-sharp-get-a-enumerator-迭代通过-sortedlist/

排序列表。GetEnumerator 方法用于一个 IDictionaryEnumerator 对象,该对象迭代一个 SortedList 对象。

语法:

public virtual System.Collections.IDictionaryEnumerator GetEnumerator ();

返回值:这个方法为 SortedList 对象返回一个 IDictionaryEnumerator 对象。

以下程序说明了上述方法的使用:

例 1:

// C# code to get IDictionaryEnumerator object
// that iterates through a SortedList object
using System;
using System.Collections;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a SortedList of integers
        SortedList mylist = new SortedList();

        // Adding elements to SortedList
        mylist.Add("1", "C++");
        mylist.Add("2", "Java");
        mylist.Add("3", "DSA");
        mylist.Add("4", "Python");
        mylist.Add("5", "C#");

        // To get an IDictionaryEnumerator
        // for the SortedList
        IDictionaryEnumerator myEnumerator = 
                             mylist.GetEnumerator();

        // If MoveNext passes the end of the
        // collection, the enumerator is positioned
        // after the last element in the collection
        // and MoveNext returns false.
        while (myEnumerator.MoveNext())
            Console.WriteLine(myEnumerator.Key + " --> "
                              + myEnumerator.Value);
    }
}

Output:

1 --> C++
2 --> Java
3 --> DSA
4 --> Python
5 --> C#

例 2:

// C# code to get IDictionaryEnumerator object
// that iterates through a SortedList object
using System;
using System.Collections;

class Geeks {

    // Main Method
    public static void Main(String[] args)
    {

        // Creating a SortedList of integers
        SortedList mylist = new SortedList();

        // Adding elements to SortedList
        mylist.Add("Australia", "Canberra");
        mylist.Add("Belgium", "Brussels");
        mylist.Add("Netherlands", "Amsterdam");
        mylist.Add("China", "Beijing");
        mylist.Add("Russia", "Moscow");
        mylist.Add("India", "New Delhi");

        // To get an IDictionaryEnumerator
        // for the SortedList
        IDictionaryEnumerator myEnumerator = 
                             mylist.GetEnumerator();

        // If MoveNext passes the end of the
        // collection, the enumerator is positioned
        // after the last element in the collection
        // and MoveNext returns false.
        while (myEnumerator.MoveNext())
            Console.WriteLine(myEnumerator.Key + " --> "
                              + myEnumerator.Value);
    }
}

Output:

Australia --> Canberra
Belgium --> Brussels
China --> Beijing
India --> New Delhi
Netherlands --> Amsterdam
Russia --> Moscow

注:

  • C# 语言的 foreach 语句隐藏了枚举器的复杂性。因此,建议使用 foreach,而不是直接操作枚举器。
  • 枚举数可用于读取集合中的数据,但不能用于修改基础集合。
  • 当前返回同一对象,直到调用移动下一个重置为止。移动下一个将当前设置为下一个元素。
  • 只要集合保持不变,枚举数就保持有效。如果对集合进行了更改,例如添加、修改或删除元素,枚举数将无法恢复地失效,并且其行为未定义。
  • 这个方法是一个 O(1)运算。

参考: