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MoveNext或Reset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