Count the number of key/value pairs in the Hashtable in C#

In C#, the Hashtable class provides the Count property to determine the number of key/value pairs stored in the collection. This property returns an integer value representing the total count of elements currently in the Hashtable.

Syntax

Following is the syntax for accessing the Count property −

int count = hashtable.Count;

Parameters

The Count property does not take any parameters. It is a read-only property that returns the current number of key/value pairs in the Hashtable.

Return Value

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

Using Count Property with Basic Operations

Example

using System;
using System.Collections;

public class Demo {
    public static void Main() {
        Hashtable hash = new Hashtable();
        hash.Add("A", "SUV");
        hash.Add("B", "MUV");
        hash.Add("C", "AUV");
        
        Console.WriteLine("Hashtable elements...");
        foreach(DictionaryEntry d in hash) {
            Console.WriteLine(d.Key + " " + d.Value);
        }
        
        Console.WriteLine("Count of Key/value pairs = " + hash.Count);
        
        hash.Add("D", "Utility Vehicle");
        hash.Add("E", "Convertible");
        
        Console.WriteLine("Count of Key/value pairs (Updated) = " + hash.Count);
    }
}

The output of the above code is −

Hashtable elements...
C AUV
A SUV
B MUV
Count of Key/value pairs = 3
Count of Key/value pairs (Updated) = 5

Using Count with Hashtable Operations

Example

using System;
using System.Collections;

public class Demo {
    public static void Main() {
        Hashtable hash = new Hashtable(10);
        hash.Add("1", "A");
        hash.Add("2", "B");
        hash.Add("3", "C");
        hash.Add("4", "D");
        hash.Add("5", "E");
        hash.Add("6", "F");
        hash.Add("7", "G");
        hash.Add("8", "H");
        hash.Add("9", "I");
        hash.Add("10", "J");
        
        Console.WriteLine("Hashtable Key and Value pairs...");
        foreach(DictionaryEntry entry in hash) {
            Console.WriteLine("{0} and {1} ", entry.Key, entry.Value);
        }
        
        Console.WriteLine("Is the Hashtable having fixed size? = " + hash.IsFixedSize);
        Console.WriteLine("Count of key/value pairs in Hashtable = " + hash.Count);
        
        Console.WriteLine("\nEnumerator to iterate through the Hashtable...");
        IDictionaryEnumerator demoEnum = hash.GetEnumerator();
        while (demoEnum.MoveNext())
            Console.WriteLine("Key = " + demoEnum.Key + ", Value = " + demoEnum.Value);
    }
}

The output of the above code is −

Hashtable Key and Value pairs...
10 and J 
1 and A 
2 and B 
3 and C 
4 and D 
5 and E 
6 and F 
7 and G 
8 and H 
9 and I 
Is the Hashtable having fixed size? = False
Count of key/value pairs in Hashtable = 10

Enumerator to iterate through the Hashtable...
Key = 10, Value = J
Key = 1, Value = A
Key = 2, Value = B
Key = 3, Value = C
Key = 4, Value = D
Key = 5, Value = E
Key = 6, Value = F
Key = 7, Value = G
Key = 8, Value = H
Key = 9, Value = I

Count Property vs Capacity

Conclusion

The Count property in C# Hashtable provides a simple and efficient way to determine the number of key/value pairs currently stored in the collection. This property is essential for checking collection size, validating operations, and implementing logic based on the number of elements in the Hashtable.