C# | Get an enumerator that iterates through the HybridDictionary

HybridDictionary.GetEnumerator method is used to return an IDictionaryEnumerator that iterates through the HybridDictionary.

Syntax:

public System.Collections.IDictionaryEnumerator GetEnumerator ();

Return Value: It returns an IDictionaryEnumerator (An Interface that enumerates the elements of a nongeneric dictionary) for the HybridDictionary.

Below programs illustrate the use of HybridDictionary.GetEnumerator Method:

Example 1:

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

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();

        // Adding key/value pairs in myDict
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");
        myDict.Add("F", "Fish");

        // To get an IDictionaryEnumerator
        // for the HybridDictionary.
        IDictionaryEnumerator myEnumerator = myDict.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:

A --> Apple
B --> Banana
C --> Cat
D --> Dog
E --> Elephant
F --> Fish

Example 2:

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

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();

        // Adding key/value pairs in myDict
        myDict.Add("I", "first");
        myDict.Add("II", "second");
        myDict.Add("III", "third");
        myDict.Add("IV", "fourth");
        myDict.Add("V", "fifth");

        // To get an IDictionaryEnumerator
        // for the HybridDictionary.
        IDictionaryEnumerator myEnumerator = myDict.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:

I --> first
II --> second
III --> third
IV --> fourth
V --> fifth

Note:

• The foreach statement of the C# language hides the complexity of the enumerators. Therefore, using foreach is recommended, instead of directly manipulating the enumerator.
• Enumerators can be used to read the data in the collection, but they cannot be used to modify the underlying collection.
• Current returns the same object until either MoveNext or Reset is called. MoveNext sets Current to the next element.
• 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.
• This method is an O(1) operation.

Reference:

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