Decoding Hashset In CSharp(C#) | Visual Studio 2022

 The C# HashSet class is a powerful data structure that allows efficient storage and retrieval of unique items. By default, HashSet uses the standard equality comparator to determine if two elements are equal. However, in some cases you may want to customize the equality comparison logic based on your specific needs. This is where the IEqualityComparer interface comes into play. This blog post explains the concept of IEqualityComparer.

What is  IEqualityComparer? 

The IEqualityComparer interface is defined in the System.Collections namespace and provides a mechanism for comparing two objects for equality. It consists of his two methods Equals and GetHashCode. The Equals method compares two objects for equality, and the GetHashCode method returns a hash code for the specified object. Implementing the IEqualityComparer interface allows you to define your own logic for comparing objects and generating hash codes. Decompiling HashSet using Visual Studio 2022:

Decompiling a HashSet using Visual Studio 2022 is a straightforward process. Let's see the steps.

Step 1: Create a new C# project in Visual Studio 2022.

Step 2: Add a reference to the System.Collections.Generic namespace.

Step 3: Define a class that implements the IEqualityComparer interface. For example, let's consider a Person class with properties like Name and Age.

public class Person

{

    public string Name { get; set; }

    public int Age { get; set; }

}

Step 4: Implement the IEqualityComparer interface by creating a custom comparer class for the Person class.

public class PersonEqualityComparer : IEqualityComparer<Person>

{

    public bool Equals(Person x, Person y)

    {

        return x.Name == y.Name && x.Age == y.Age;

    }

    public int GetHashCode(Person obj)

    {

        return obj.Name.GetHashCode() ^ obj.Age.GetHashCode();

    }

}

Step 5: In the Main method, create a HashSet of Person objects using the custom comparer.

static void Main(string[] args)

{

    HashSet<Person> persons = new HashSet<Person>(new PersonEqualityComparer());

    persons.Add(new Person { Name = "John", Age = 30 });

    persons.Add(new Person { Name = "Jane", Age = 25 });

    persons.Add(new Person { Name = "John", Age = 30 }); // Duplicate entry

    foreach (var person in persons)

    {

        Console.WriteLine($"Name: {person.Name}, Age: {person.Age}");

    }

}

Step 6: Build and run the project. You can see that no duplicate entries were added to the HashSet because the equality comparison uses a custom comparator defined in the PersonEqualityComparer class.

Check out the detailed video on Hashset : 

Suggested Reads : C# Tips

Conclusion:

This blog post explained the concept of IEqualityComparer and its use in his HashSet in C#. I learned how to create a custom equality comparator for a specific class and use it to compare and hash objects in his HashSet. Implementing the IEqualityComparer interface allows you to customize the equality comparison logic based on your needs. Decompiling a HashSet with Visual Studio 2022 is a straightforward process, and you can use the IEqualityComparer implementation to control the collection's equality semantics.

If you need to use custom equality logic in your C# project, remember that it's helpful to understand the application using the IEqualityComparer and its HashSet.