C# | Get an IDictionaryEnumerator object in OrderedDictionary

OrderedDictionary.GetEnumerator method returns an IDictionaryEnumerator object that iterates through the OrderedDictionary collection.

Syntax:

public virtual System.Collections.IDictionaryEnumerator GetEnumerator ();

Return Value: An IDictionaryEnumerator object for the OrderedDictionary collection.

Below given are some examples to understand the implementation in a better way:

Example 1:

// C# code to get an IDictionaryEnumerator
// object that iterates through the
// OrderedDictionary collection.
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("key1", "value1");
        myDict.Add("key2", "value2");
        myDict.Add("key3", "value3");
        myDict.Add("key4", "value4");
        myDict.Add("key5", "value5");

        // To Get an IDictionaryEnumerator object
        // that iterates through the OrderedDictionary
        // collection.
        IDictionaryEnumerator myEnumerator = myDict.GetEnumerator();

        while (myEnumerator.MoveNext()) {
            Console.WriteLine(myEnumerator.Key + " --> "
                                  + myEnumerator.Value);
        }
    }
}

Output:

key1 --> value1
key2 --> value2
key3 --> value3
key4 --> value4
key5 --> value5

Example 2:

// C# code to get an IDictionaryEnumerator
// object that iterates through the
// OrderedDictionary collection.
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver method
    public static void Main()
    {

        // Creating a orderedDictionary named myDict
        OrderedDictionary myDict = new OrderedDictionary();

        // Adding key and value in myDict
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");

        // To Get an IDictionaryEnumerator object
        // that iterates through the OrderedDictionary
        // collection.
        IDictionaryEnumerator myEnumerator = myDict.GetEnumerator();

        while (myEnumerator.MoveNext()) {
            Console.WriteLine(myEnumerator.Key + " --> "
                                 + myEnumerator.Value);
        }
    }
}

Output:

A --> Apple
B --> Banana
C --> Cat
D --> Dog

Note:

• Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.
• Initially, the enumerator is positioned before the first element in the collection.
• This method is an O(1) operation.
• An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and its behavior is undefined.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.ordereddictionary.getenumerator?view=netframework-4.7.2