Get an enumerator that iterates through the Dictionary in C#

To get an enumerator that iterates through a Dictionary in C#, you use the GetEnumerator() method which returns an IDictionaryEnumerator. This enumerator provides access to both keys and values as you iterate through the dictionary's key-value pairs.

Syntax

Following is the syntax for getting a Dictionary enumerator −

IDictionaryEnumerator enumerator = dictionary.GetEnumerator();

The enumerator is used with MoveNext() to advance through the collection −

while (enumerator.MoveNext()) {
    Console.WriteLine("Key = " + enumerator.Key + ", Value = " + enumerator.Value);
}

Using Dictionary Enumerator with Integer Keys

Example

using System;
using System.Collections;
using System.Collections.Generic;

public class Demo {
    public static void Main() {
        Dictionary<int, string> dict = new Dictionary<int, string>();
        dict.Add(100, "Laptop");
        dict.Add(150, "Desktop");
        dict.Add(200, "Earphone");
        dict.Add(300, "Tablet");
        dict.Add(500, "Speakers");
        dict.Add(750, "HardDisk");
        dict.Add(1000, "SSD");
        
        IDictionaryEnumerator demoEnum = dict.GetEnumerator();
        Console.WriteLine("Enumerator iterating key-value pairs...");
        
        while (demoEnum.MoveNext())
            Console.WriteLine("Key = " + demoEnum.Key + ", Value = " + demoEnum.Value);
    }
}

The output of the above code is −

Enumerator iterating key-value pairs...
Key = 100, Value = Laptop
Key = 150, Value = Desktop
Key = 200, Value = Earphone
Key = 300, Value = Tablet
Key = 500, Value = Speakers
Key = 750, Value = HardDisk
Key = 1000, Value = SSD

Using Dictionary Enumerator with String Keys

Example

using System;
using System.Collections;
using System.Collections.Generic;

public class Demo {
    public static void Main() {
        Dictionary<string, string> dict = new Dictionary<string, string>();
        dict.Add("One", "Laptop");
        dict.Add("Two", "Desktop");
        dict.Add("Three", "Earphone");
        dict.Add("Four", "Tablet");
        dict.Add("Five", "Speakers");
        dict.Add("Six", "HardDisk");
        dict.Add("Seven", "SSD");
        dict.Add("Eight", "Keyboard");
        dict.Add("Nine", "Mouse");
        
        IDictionaryEnumerator demoEnum = dict.GetEnumerator();
        Console.WriteLine("Enumerator iterating key-value pairs...");
        
        while (demoEnum.MoveNext())
            Console.WriteLine("Key = " + demoEnum.Key + ", Value = " + demoEnum.Value);
    }
}

The output of the above code is −

Enumerator iterating key-value pairs...
Key = One, Value = Laptop
Key = Two, Value = Desktop
Key = Three, Value = Earphone
Key = Four, Value = Tablet
Key = Five, Value = Speakers
Key = Six, Value = HardDisk
Key = Seven, Value = SSD
Key = Eight, Value = Keyboard
Key = Nine, Value = Mouse

Alternative Iteration Methods

While GetEnumerator() provides fine-grained control, C# offers more convenient ways to iterate through dictionaries −

Using foreach with KeyValuePair

using System;
using System.Collections.Generic;

public class Demo {
    public static void Main() {
        Dictionary<int, string> dict = new Dictionary<int, string>();
        dict.Add(1, "First");
        dict.Add(2, "Second");
        dict.Add(3, "Third");
        
        Console.WriteLine("Using foreach with KeyValuePair:");
        foreach (KeyValuePair<int, string> pair in dict) {
            Console.WriteLine("Key = " + pair.Key + ", Value = " + pair.Value);
        }
    }
}

The output of the above code is −

Using foreach with KeyValuePair:
Key = 1, Value = First
Key = 2, Value = Second
Key = 3, Value = Third

Key Properties of IDictionaryEnumerator

Conclusion

The GetEnumerator() method returns an IDictionaryEnumerator that allows manual iteration through Dictionary key-value pairs using MoveNext(). While this approach provides control over the iteration process, modern C# applications typically use foreach loops with KeyValuePair for simpler and more readable code.