Understanding Constructors (C#)


What is constructor?

Constructor is a special type of function member of a class. It is used to initialize the instance variables of the object.

Person myPerson=new Person();

Here the new operator is used to allocate the memory needed to store the data of the object.

Now suppose this is how we have defined our Person class.

  public class Person
        {
            public string FirstName { get; set; }
            public string LastName { get; set; }
        }  
   

( here we have used Automatic Properties feature of C# 3.0 to declare our properties FirstName and LastName)

Here in our class we haven’t defined a constructor but we are still able to create instance variables of the Person Object using following line of code

Person p = new Person();
 

The reason it is possible is because we don’t have to explicitly declare constructor for a class, C# automatically provides a default parameterless constructor for that class. The default constructor will initialize any fields of the class to their zero-equivalent values.

We can also write our own constructors, the things to remember are

  • They don’t have a return type.
  • Their name should be same as the name of the class.
  • Should contain a parameter list, which could be left empty.

Now the question is why would we be writing our own constructors?

Well the reason is because constructors can be used to pass initial values for an object’s fields at the time when an object is being instantiated.

For our above Person class

instead of the following code 

    Person p = new Person();
    p.FirstName = "Nishant";
    p.LastName = "Rana";

 

we can do the same in single line of code

Person p = new Person("Nishant", "Rana");
 

The constructor would be defined in the following manner

 public Person(string fname, string lname)
          {
              FirstName = fname;
              LastName = lname;
          }

One thing we have to remember is that if we are defining our own Parameterized constructor the default constructor would be eliminated.

We won’t be able to create person class object using default constructor.

i.e. Person p=new Person(); // it won’t compile.

In this case then we need to explicitly write a default constructor.

public Person()
        { 

        }

bye..

Author: Nishant Rana

I love working in and sharing everything about Microsoft.NET technology !

One thought on “Understanding Constructors (C#)”

Please share your thoughts

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Welcome to the Blog & Website of Paul Andrew

Technical Leadership Centred Around the Microsoft Data Platform

Deriving Dynamics 365

Deriving Solutions and features on Power Platform/Dynamics 365

The CRM Ninja

Thoughts & musings from a Dynamics 365 Ninja!

CRM for You and Me

Customer Relationship Mgt App for the Professional

D CRM Explorer

Learn about Microsoft Dynamics CRM Power Platform customization and implementation and other cool stuffs

Stroke // Jonas Rapp

I know pre-stroke. I will improve who I was.

Power Melange

Power Melange By Shalinee

Clavin's Blog

Power Automate - Power Apps - SharePoint Online - Azure - Nintex - K2 - Artificial Intelligence

Sat Sangha Salon

An Inquiry in Being

The Indoencers

The Influencers & Influences of Indian Music

Monika Halan's blog

Hand's-free money management

D365 Demystified

A closer look at Microsoft Dynamics 365.

Microsoft Mate (msftmate) - Andrew Rogers

Experienced consultant primarily focused on Microsoft Dynamics 365 and the Power Platform

Knowhere365

Specific topics by Django Lohn on the whole Microsoft365 Stack

Manmit Rahevar's Blog

One Stop Destination for Microsoft Technology Solutions

MG

Naturally Curious

Brian Illand

Power Platform and Dynamics 365

Steve Mordue MVP

A Microsoft Business Applications MVP

Subwoofer 101

Bass defines your home theater

SQLTwins by Nakul Vachhrajani

SQL Server tips and experiences dedicated to my twin daughters.

Everything D365

Discovering Azure DevOps and D365 Business Applications

Tech Wizard

Lets do IT Spells

XRM Tricks (Power Platform & Dynamics CRM )

Power Platform & Dynamics CRM

CRM TIPS BY PRM

Mail to crmtipsbyprm@gmail.com for queries and suggestions

nijos.dev

Giving back to the community what I have learned

xrm CRM Dynamics

Dynamics CRM Technical & Functional Info

Dynamics 365 Blogs - Explained in unique way

Sometimes you need to look at things from different perspective.

CRM Keeper

Dynamics 365 Customer Engagement, CRM, Microsoft CRM, Dynamics CRM

EVOLVED365

Step into the world of a Dynamics 365 Consultant

Dianamics PCF Lady

Diana & Dynamics 365 & Power Platform

Sara Lagerquist

No Code Customization Concepts

innovativeaj

developer, designer, writer, fun loving, patriotic, humble and a sweet person inside out :) love and respect people who have a great sense of humor.

Temmy Wahyu Raharjo

dreaming to be a clean coder and TDD minded programmer.

%d bloggers like this: