Get the number of key/value pairs contained in ListDictionary in C#

To get the number of key/value pairs contained in ListDictionary, you use the Count property. The ListDictionary class in C# is part of the System.Collections.Specialized namespace and is optimized for small collections with typically fewer than 10 elements.

The Count property returns an integer representing the total number of key/value pairs currently stored in the ListDictionary.

Syntax

Following is the syntax for getting the count of key/value pairs in ListDictionary −

ListDictionary listDict = new ListDictionary();
int count = listDict.Count;

Using Count Property

Example

using System;
using System.Collections;
using System.Collections.Specialized;

public class Demo {
   public static void Main(){
      ListDictionary dict1 = new ListDictionary();
      dict1.Add("A", "Books");
      dict1.Add("B", "Electronics");
      dict1.Add("C", "Smart Wearables");
      dict1.Add("D", "Pet Supplies");
      dict1.Add("E", "Clothing");
      dict1.Add("F", "Footwear");
      Console.WriteLine("ListDictionary1 elements...");
      foreach(DictionaryEntry d in dict1){
         Console.WriteLine(d.Key + " " + d.Value);
      }
      ListDictionary dict2 = new ListDictionary();
      dict2.Add("1", "One");
      dict2.Add("2", "Two");
      dict2.Add("3", "Three");
      dict2.Add("4", "Four");
      dict2.Add("5", "Five");
      dict2.Add("6", "Six");
      Console.WriteLine("\nListDictionary2 elements...");
      foreach(DictionaryEntry d in dict2){
         Console.WriteLine(d.Key + " " + d.Value);
      }
      Console.WriteLine("Count of key/value pairs in Dictionary 2 = "+dict2.Count);
      ListDictionary dict3 = new ListDictionary();
      dict3 = dict2;
      Console.WriteLine("\nIs ListDictionary3 equal to ListDictionary2? = "+(dict3.Equals(dict2)));
      dict3.Clear();
      Console.WriteLine("Count of key/value pairs in Dictionary 3 = "+dict3.Count);
   }
}

The output of the above code is −

ListDictionary1 elements...
A Books
B Electronics
C Smart Wearables
D Pet Supplies
E Clothing
F Footwear

ListDictionary2 elements...
1 One
2 Two
3 Three
4 Four
5 Five
6 Six
Count of key/value pairs in Dictionary 2 = 6

Is ListDictionary3 equal to ListDictionary2? = True
Count of key/value pairs in Dictionary 3 = 0

Count with Different Operations

Example

using System;
using System.Collections;
using System.Collections.Specialized;

public class Demo {
   public static void Main(){
      ListDictionary dict1 = new ListDictionary();
      dict1.Add("A", "Books");
      dict1.Add("B", "Electronics");
      dict1.Add("C", "Smart Wearables");
      dict1.Add("D", "Pet Supplies");
      dict1.Add("E", "Clothing");
      Console.WriteLine("ListDictionary1 elements...");
      foreach(DictionaryEntry d in dict1){
         Console.WriteLine(d.Key + " " + d.Value);
      }
      Console.WriteLine("Count of key/value pairs in Dictionary1 = "+dict1.Count);
      ListDictionary dict2 = new ListDictionary();
      dict2.Add("1", "One");
      dict2.Add("2", "Two");
      dict2.Add("3", "Three");
      dict2.Add("4", "Four");
      dict2.Add("5", "Five");
      dict2.Add("6", "Six");
      Console.WriteLine("\nListDictionary2 key-value pairs...");
      IDictionaryEnumerator demoEnum = dict2.GetEnumerator();
      while (demoEnum.MoveNext())
         Console.WriteLine("Key = " + demoEnum.Key + ", Value = "+ demoEnum.Value);
      Console.WriteLine("Count of key/value pairs in Dictionary2 = "+dict2.Count);
   }
}

The output of the above code is −

ListDictionary1 elements...
A Books
B Electronics
C Smart Wearables
D Pet Supplies
E Clothing
Count of key/value pairs in Dictionary1 = 5

ListDictionary2 key-value pairs...
Key = 1, Value = One
Key = 2, Value = Two
Key = 3, Value = Three
Key = 4, Value = Four
Key = 5, Value = Five
Key = 6, Value = Six
Count of key/value pairs in Dictionary2 = 6

Count Behavior with Operations

Example - Count After Various Operations

using System;
using System.Collections.Specialized;

public class Demo {
   public static void Main(){
      ListDictionary dict = new ListDictionary();
      Console.WriteLine("Initial count: " + dict.Count);
      
      dict.Add("X", "First");
      dict.Add("Y", "Second");
      dict.Add("Z", "Third");
      Console.WriteLine("After adding 3 items: " + dict.Count);
      
      dict.Remove("Y");
      Console.WriteLine("After removing 1 item: " + dict.Count);
      
      dict.Clear();
      Console.WriteLine("After clearing: " + dict.Count);
   }
}

The output of the above code is −

Initial count: 0
After adding 3 items: 3
After removing 1 item: 2
After clearing: 0

Conclusion

The Count property of ListDictionary provides an efficient way to get the number of key/value pairs in the collection. It automatically updates as you add, remove, or clear items, making it useful for validation, loops, and conditional operations based on collection size.