Dictionary.Count Property in C#

The Dictionary.Count property in C# gets the number of key/value pairs contained in the Dictionary<TKey, TValue>. This property is read-only and provides an efficient way to determine the size of your dictionary collection.

Syntax

public int Count { get; }

Return Value

The property returns an int representing the total number of key/value pairs in the dictionary. The count is automatically updated when items are added or removed.

Using Dictionary.Count Property

Basic Usage Example

The following example demonstrates how to use the Count property to track dictionary size −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      Dictionary<string, string> dict = new Dictionary<string, string>();
      
      dict.Add("One", "Chris");
      dict.Add("Two", "Steve");
      dict.Add("Three", "Messi");
      dict.Add("Four", "Ryan");
      dict.Add("Five", "Nathan");
      
      Console.WriteLine("Count of elements = " + dict.Count);
      Console.WriteLine("\nKey/value pairs...");
      
      foreach(KeyValuePair<string, string> res in dict) {
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
      
      if (dict.ContainsValue("Angelina"))
         Console.WriteLine("Value found!");
      else
         Console.WriteLine("Value isn't in the dictionary!");
      
      dict.Clear();
      Console.WriteLine("Cleared Key/value pairs...");
      
      foreach(KeyValuePair<string, string> res in dict) {
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
      
      Console.WriteLine("Count of elements now = " + dict.Count);
   }
}

The output of the above code is −

Count of elements = 5

Key/value pairs...
Key = One, Value = Chris
Key = Two, Value = Steve
Key = Three, Value = Messi
Key = Four, Value = Ryan
Key = Five, Value = Nathan
Value isn't in the dictionary!
Cleared Key/value pairs...
Count of elements now = 0

Tracking Count Changes

The following example shows how the count changes as elements are added and removed −

using System;
using System.Collections.Generic;

public class Demo {
   public static void Main() {
      Dictionary<int, string> dict = new Dictionary<int, string>();
      
      Console.WriteLine("Initial count: " + dict.Count);
      
      dict.Add(1, "Apple");
      dict.Add(2, "Banana");
      Console.WriteLine("After adding 2 items: " + dict.Count);
      
      dict[3] = "Cherry";
      dict[4] = "Date";
      Console.WriteLine("After adding 2 more items: " + dict.Count);
      
      dict.Remove(2);
      Console.WriteLine("After removing 1 item: " + dict.Count);
      
      dict.Clear();
      Console.WriteLine("After clearing all items: " + dict.Count);
   }
}

The output of the above code is −

Initial count: 0
After adding 2 items: 2
After adding 2 more items: 4
After removing 1 item: 3
After clearing all items: 0

Common Use Cases

• Validation − Check if dictionary is empty before processing

• Loop conditions − Use count in for loops or conditional statements

• Capacity management − Monitor dictionary size for performance optimization

• Progress tracking − Display processing progress based on dictionary size

Conclusion

The Dictionary.Count property provides an efficient O(1) way to get the number of key/value pairs in a dictionary. It automatically updates as items are added or removed and is essential for dictionary size validation and loop operations.