📜  C#|获取一个遍历SortedList的枚举数

📅  最后修改于: 2021-05-29 20:34:47             🧑  作者: Mango

SortedList.GetEnumerator方法用于迭代通过SortedList对象的IDictionaryEnumerator对象。

句法:

public virtual System.Collections.IDictionaryEnumerator GetEnumerator ();

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

下面的程序说明了上面讨论的方法的使用:

范例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);
    }
}
输出:
1 --> C++
2 --> Java
3 --> DSA
4 --> Python
5 --> C#

范例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);
    }
}
输出:
Australia --> Canberra
Belgium --> Brussels
China --> Beijing
India --> New Delhi
Netherlands --> Amsterdam
Russia --> Moscow

笔记:

  • 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。
  • 在调用MoveNextReset之前,Current返回相同的对象。 MoveNext将Current设置为下一个元素。
  • 只要集合保持不变,枚举数将保持有效。如果对集合进行了更改(例如添加,修改或删除元素),则枚举数将无法恢复,并且其行为是不确定的。
  • 此方法是O(1)操作。

参考:

  • https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.sortedlist.getenumerator?view=netframework-4.7.2