How to Create a Generic Dictionary in C#

The following program demonstrates How to Create a Generic Dictionary in C#.

In order to create a generic dictionary, we need to use the generic Dictionary class available in the System.Collections.Generic namespace. Since the Dictionary stores the collection of key-value pairs, we need to specify the data types for both keys and values. Here we take keys and values as integers. The Add() method inserts a key-value pair. Similarly, the Remove() method deletes a key-value pair.

using System;
using System.Collections.Generic;
namespace DictionaryClassDemo
{
    // Demonstration of Generic Dictionary
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<int, int> d1 = new Dictionary<int, int>();
            d1.Add(1, 10);
            d1.Add(2, 20);
            d1.Add(3, 30);
            d1.Add(4, 40);
            d1.Add(5, 50);
            d1.Add(6, 60);
            d1.Add(7, 70);
            d1.Add(8, 80);
            d1.Add(9, 90);

            // Item Property of the Dictionary
            for (int i = 1; i <= 9; i++)
                Console.WriteLine(d1[i].ToString());
            // Count property
            Console.WriteLine($"Total Key/Value pairs in the dictionary: {d1.Count}");

            // Display the collection of keys in the dictionary
            Console.WriteLine("Displying keys...");
            foreach(int k in d1.Keys)
            {
                Console.Write(k+" ");
            }
            Console.WriteLine();

            // Display the collection of values in the dictionary
            Console.WriteLine("Displying values...");
            foreach (int v in d1.Values)
            {
                Console.Write(v + " ");
            }
            Console.WriteLine();

            //Removing Keys from the dictionary
            d1.Remove(5);
            d1.Remove(8);
            //Display values after removing some keys
            Console.WriteLine("Displaying values after removing some keys...");
            foreach(KeyValuePair<int, int> k in d1)
            {
                Console.WriteLine($"Key: {k.Key}, Value: {k.Value}");
            }
            int a = 3;
            Console.WriteLine($"Dictionary contains the Key {a}: {d1.ContainsKey(a)}");
            a = 5;
            Console.WriteLine($"Dictionary contains the Key {a}: {d1.ContainsKey(a)}");
            a = 90;
            Console.WriteLine($"Dictionary contains the value {a}: {d1.ContainsValue(a)}");
            a = 80;
            Console.WriteLine($"Dictionary contains the value {a}: {d1.ContainsValue(a)}");

            //Using TryGetValues
            Console.WriteLine("Displaying values in the Dictionary using TryGetValues()...");
            int v1;
            for (int i = 1; i <= 9; i++)
            {
                if(d1.TryGetValue(i, out v1))
                Console.WriteLine(v1);
            }
        }
    }
}

Output

**A Program to Demonstrate How to Create a Generic Dictionary in C#**

Further Reading