Unable to add controller to ASP.NET, Controller option greyed out / disabled

 If you are unable to add controller to ASP.NET due to controller option being greyed out. Please check out my 1 minute youtube video which provides solution to this issue. 

Thank you very much,

How to install Nuget Package in Visual Studio 2022

 I've linked my YouTube video below, where I explain how to install Nuget Package in Visual Studio 2022

How to check .NET (dot net) framework version in Visual Studio Code (VS Code).

I've linked my YouTube video below, where I explain how to check .NET (dot net) framework version in Visual Studio Code (VS Code).

Understanding C# Interface under 10 minutes with example and a coding challenge

 I've linked my YouTube video below, where I explain interface in C# with a practical example and a fun coding challenge at the end. Below the video, you'll find the actual code featured in the tutorial.

Try solving the coding challenge yourself before checking out the solution provided at the end of this blog - it’s a fantastic way to test your understanding and sharpen your skills! Happy coding! 😊

Actual code featured in the tutorial

using System;
using System.Collections.Generic;

namespace Interface_App
{
    internal class Program
    {
        static void Main(string[] args)
        {
            List flyingThings = new List
            {
                new People(),
                new Airplane()
            };

            foreach (var thing in flyingThings)
            {
                thing.Fly();
                thing.Glide();
                Console.WriteLine();
            }

            List speakingThings = new List
            {
                new People()
            };

            foreach (var thing in speakingThings)
            {
                thing.Speak();
                Console.WriteLine();
            }
        }      
        
    }


    interface IAirActivities
    {
        void Fly();
        void Glide();
    }

    interface ISpeaking
    {
        void Speak();
    }

    public class People : IAirActivities, ISpeaking
    {
        public void Fly()
        {
            Console.WriteLine("People who fly airplanes are called pilot.");
        }

        public void Glide()
        {
            Console.WriteLine("People can glide in the air using gliders.");
        }

        public void Speak()
        {
            Console.WriteLine("People can speak at least one language.");
        }
    }
    
    public class Airplane : IAirActivities
    {
        public void Fly()
        {
            Console.WriteLine("Airplanes are able to fly in the sky");
        }

        public void Glide()
        {
            Console.WriteLine("Airplanes can glide with their engines off");
        }
    }

}

---

Interface coding challenge solution

Below is the solution to the coding challenge featured in the video. 

using System;
using System.Collections.Generic;


namespace InterfaceExcerciseApp
{
    internal class Program
    {
        static void Main(string[] args)
        {
            IAnimal lion = new Lion();
            IAnimal parrot = new Parrot();
            IAnimal snake = new Snake();
            
            List animals = new List { lion, parrot, snake};
            

            foreach (IAnimal animal in animals)
            {
                Console.WriteLine(animal.Eat());
                Console.WriteLine(animal.MakeSound());
                Console.WriteLine();
            }
        }
    }

    public interface IAnimal
    {
        string Eat();
        string MakeSound();
    }

    public class Lion : IAnimal
    {
        public string Eat()
        {
            return "Lions eat meat";
        }

        public string MakeSound()
        {
            return "Lion roars"; 
        }   
    }

    public class Parrot : IAnimal
    {
        public string Eat()
        {
            return "Parrots eat nuts.";
        }

        public string MakeSound()
        {
            return "Parrots sing";
        }
    }

    public class Snake : IAnimal
    {
        public string Eat()
        {
            return "Snakes eat rodents.";
        }

        public string MakeSound()
        {
            return "Snakes hiss.";
        }
    }
}




CSharp C# Method Overloading with Practical Example and Coding Challenge / Coding Excercise

I've linked my YouTube video below, where I explain method overloading in C# with a practical example and a fun coding challenge at the end. Below the video, you'll find the actual code featured in the tutorial.

Try solving the coding challenge yourself before checking out the solution provided at the end of this blog - it’s a fantastic way to test your understanding and sharpen your skills! Happy coding! 😊

Actual code featured in the tutorial

using System;

namespace MethodOverLoading
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Log log = new Log();
            log.DisplayLog("Welcome to this program.");
            log.DisplayLog("You have successfully created the file on ", DateTime.Now);
            log.DisplayLog("Requires user authentication", 401);
        }
    }

    public class Log
    {
        public void DisplayLog(string message)
        {
            Console.WriteLine(message);
        }
        public void DisplayLog(string message, DateTime dateAndTime)
        {
            Console.WriteLine($"{message}, {dateAndTime}");
        }
        public void DisplayLog(string error, int errorCode)
        {
            Console.WriteLine($"{error}, error code: {errorCode}");
        }
    }
}

---

Method Overloading coding challenge solution

Below is the solution to the coding challenge featured in the video. In this example, I’ve used the double data type for the square and rectangle area parameters, and int for the circle area. However, feel free to use any data types you prefer—as long as the method signatures are different, your solution will work perfectly for this challenge.

using System;

namespace MethodOverLoadingExcercise
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Area(3.0);
            Area(1.5, 4);
            Area(4);
        }

        //area of a square
        public static double Area(double length)
        {
            //if decimal, then round to 2 decimal places
            double output = Math.Round(length * length, 2);

            Console.WriteLine($"Area of square: {output}");

            return output;
        }

        //area of a rectangle
        public static double Area(double length1, double length2)
        {
            double output = Math.Round(length1 * length2, 2);

            Console.WriteLine($"Area of rectangle: {output}");

            return output;
        }

        /* area of a circle
        We use an integer parameter for the radius to make this 
        method's signature unique compared to the square's area method. 
        This is important because both shapes involve a single numeric input.
         */
        public static double Area(int radius)
        {
            //const means variable is a constant
            const double pi = Math.PI;

            //Area of a circle = pi * r * r, rounded to 2 decimals
            double output = Math.Round(pi * radius * radius, 2);

            Console.WriteLine($"Area of circle: {output}");

            return output;
        }
    }
    
}

CSharp C# Method Overriding in with a Practical Example and Coding Challenge

I've linked my YouTube video below, where I explain method overriding in C# with a practical example and a fun coding challenge at the end. Below the video, you'll find the actual code featured in the tutorial.

I have used virtual method in the example so i have used abstract class and method for the coding challenge solution. You can solve using both ways. Try solving the coding challenge yourself before checking out the solution provided at the end of this blog - it’s a fantastic way to test your understanding and sharpen your skills! Happy coding! 😊

Actual code featured in the youtube tutorial above

using System;

namespace Method_Overriding
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Engineer engineer = new Engineer();
            engineer.Work();

            FrontEndEngineer frontEnd = new FrontEndEngineer();
            frontEnd.Work();

            BackEndEngineer backEnd = new BackEndEngineer();
            backEnd.Work();

            DevOpsEngineer devOps = new DevOpsEngineer();
            devOps.Work();
        }
    }

    public class Engineer   //Parent class, base class, superclass
    {
        public virtual void Work()
        {
            Console.WriteLine("All engineers need to work");
        }
    }

    public class FrontEndEngineer : Engineer //Child class, derived class
    {
        public override void Work()
        {
            Console.WriteLine("Front end engineers creates the user interface of website and application");
        }
    }

    public class BackEndEngineer : Engineer    
    {
        public override void Work()
        {
            Console.WriteLine("Back end engineers creates and maintains the serverside of application");
        }
    }

    public class DevOpsEngineer : Engineer
    {
        public override void Work()
        {
            Console.WriteLine("Dev ops engineers maintains the companies software operation");
        }
    }
}

Method Overriding Coding Challenge Solution

using System;

namespace MethodOverridingExcerciseDemo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Remote TV = new Tv();
            TV.PressPlay();

            Remote MusicPlayer = new MusicPlayer();
            MusicPlayer.PressPlay();

            Remote VideoGameConsole = new VideoGameConsole();
            VideoGameConsole.PressPlay();
        }
    }

    //Remote considered as abstract and it will be our parent class
    public abstract class Remote
    {
        public abstract void PressPlay(); //abstract method has no body
    }

    public class Tv : Remote
    {
        public override void PressPlay()
        {
            Console.WriteLine("Starting a movie.");
        }
    }

    public class MusicPlayer : Remote
    {
        public override void PressPlay()
        {
            Console.WriteLine("Starting a song");
        }
    }

    public class VideoGameConsole : Remote
    {
        public override void PressPlay()
        {
            Console.WriteLine("Starting a game");
        }
    }
}

Understanding Classes in C#

Introduction

In C# class is a blueprint for creating objects. It contains data (properties) and behaviour (methods). We can build multiple objects with distinct properties and methods using classes without having to repeat the code.

Class Syntax: Creating a generic C# Class

public class Car    //car is the class name and Pascal case
{
    public string Model { get; set; }	//properties
    public string Color { get; set; }

    public void Start()					//method
    {
        Console.WriteLine("Car started.");
    }

    public void Stop()					//method
    {
        Console.WriteLine("Car stopped.");
    }
}

A generic class in C# is created using a class keyword followed by class name. Class name, property name, method name must always be Pascal case i.e. Starting letter must be capital case. Class can have different properties and methods. We cannot use the class directly without creating an object. In order to use class we must create an object which is an instance of class.

Creating an object

Once class is created. Object can be creating by instantiating a class with the new keyword. Attributes can be initialized using the dot operator followed by attribute name as shown below.

Car myCar = new Car();
myCar.Model = "Toyota Camry";
myCar.Color = "Red";
myCar.Start();

We can also create an object and initialize attributes directly using { }

Car myCar = new Car
{
    Model = "Toyota Camry",
    Color = "Red"
};

Creating object using constructor

We can also create an object and initialize attributes directly using constructor. Constructor name must be same as class name. Arguments are passed in to the constructor. this keyword is used to link arguments to attributes.

 public class Car
 {
     public string Model { get; set; }
     public string Color { get; set; }

     public Car(string model, string color) //Constructor
     {
         this.Model = model;
         this.Color = color;
     }

     public void Start()
     {
         Console.WriteLine("Car started.");
     }

     public void Stop()
     {
         Console.WriteLine("Car stopped.");
     }
}

Once the constructor is set in a class we can now create an object by directly passing in values to the constructor.

Car myCar = new Car("Mercedes", "blue");
Console.WriteLine(myCar.Model);   //outputs Mercedes
Console.WriteLine(myCar.Color);   //outputs blue

Types of classes

Regular Classes

Abstract Classes

Static Classes

Partial Classses

Regular Class: Needs to be instantiated to create objects. These are the most common type. Examples shown above so far are regular classes.

Abstract Class: Abstract classes are something that exists as generic idea but does not physically exist. For e.g. vehicle can be anything a bike, truck, car, lorry, boat etc. Abstract classes cannot be instantiated directly. They serve as a base class for other classes, providing a common interface. Abstract class can have its own properties and methods. All derived classes must provide their own implementation for these properties and methods. Abstract class is created using abstract keyword.

public abstract class Vehicle
    {
        //Abstract properties and methods (no implementation)
        public abstract string Model { get; set; }
        public abstract string Color { get; set; } 
        public abstract void Start();
        public abstract void Stop();
    }

Once public class is created. We can use this public class as a base class as follows. Each abstract properties and methods must be implemented during this phase.

public class Car : Vehicle
    {
        //implementing abstract properties
        public override string Model { get; set; }
        public override string Color { get; set; }

        //constructor
        public Car(string model, string color)
        {
            Model = model;  //can also write this.Model
            Color = color;  //can also write this.Color
        }
		
        //implementing abstract method
        public override void Start()
        {
            Console.WriteLine($"{Model} car started.");
        }

        public override void Stop()
        {
            Console.WriteLine($"{Model} car stopped.");
        }
    }

    public class Truck : Vehicle
    {
    	//implementing abstract properties
        public override string Model { get; set; }
        public override string Color { get; set; }

        //constructor
        public Truck(string model, string color)
        {
            Model = model;  //can also write this.Model
            Color = color;  //can also write this.Color
        }
		
        //implementing abstract method
        public override void Start()
        {
            Console.WriteLine($"{Model} truck started.");
        }

        public override void Stop()
        {
            Console.WriteLine($"{Model} truck stopped.");
        }
    }

Once the abstract class is created and implemented on its derived class then we can use it by creating objects from the derived class.

internal class Program
    {
        static void Main(string[] args)
        {
            Car myCar = new Car("BMW", "red"); //Car is the derived class
            myCar.Start();		//BMW car started.
            myCar.Stop();		//BMW car stopped.

            Truck myTruck = new Truck("Tesla", "silver");
            myTruck.Start();    // Tesla truck started.
            myTruck.Stop();		//Tesla truck stopped.
        }
    } 

Static Class: Static class cannot be instantiated and can be used directly. All members of a static class must be static. An example is shown below

public static class CarUtilities
{
    public static void displayInformation(Car car)
    {
        Console.WriteLine($"Model: {car.Model}");
        Console.WriteLine($"Color: {car.Color}");
    }
}

Partial Class:Partial class can be defined across multiple files. This is useful for splitting large class definitions into smaller, more manageable parts.

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I have also created a youtube video about this topic please feel free to check it out. Happy coding.