Factory Design Pattern in C# with Real-Time Example

 Here we will discuss the Factory Design Pattern in C#. it is a type of  Creational Design Pattern.

Factory Design Pattern in C#?

As per Gang of Four, Factory Design Pattern is that “Define an interface for creating an object but let sub-classes decide which class to instantiate. The Factory method class defers instantiation it uses to the sub-classes”. In the Factory pattern, we create product objects without exposing the logic to the end user.

Without creating Factory Design Pattern in C#

1. create a below interface

public interface Cars     {         string GetCarModel();         string GetColor();         int GetCarPrice();     }

 2. Now create CarModel classes

    1. HondaModelCars.cs

 

public class HondaModelCars: Cars     {         public string GetCarModel()         {             return "Honda Model";         }         public string GetColor()         {             return "Red";         }         public int GetCarPrice()         {             return 100000;         }     }

2. BMWModelCars.cs

 

public class BMWModelCars: Cars     {         public string GetCarModel()         {             return "BMW Model";         }         public string GetColor()         {             return "Black";         }         public int GetCarPrice()         {             return 200000;         }     }

3. FerrariModelCars.cs

 

public class FerrariModelCars: Cars     {         public string GetCarModel()         {             return "Ferrari Model";         }         public string GetColor()         {             return "Blue";         }         public int GetCarPrice()         {             return 500000;         }     }

Now let's run this application from the main method like below

 

static void Main(string[] args)         {             Console.WriteLine("Enter the Car Model : ");               string carModel = Console.ReadLine();             Cars carsDetails = null;                      if (carModel.ToLower() == "honda")             {                 carsDetails = new HondaModelCars();             }             else if (carModel.ToLower() == "bmw")             {                 carsDetails = new BMWModelCars();             }             else if (carModel.ToLower() == "ferrari")             {                 carsDetails = new FerrariModelCars();             }             if (carsDetails != null)             {                 Console.WriteLine("Car Model : " + carsDetails.GetCarModel());                 Console.WriteLine("Car color : " + carsDetails.GetColor());                 Console.WriteLine("Car price :" + carsDetails.GetCarPrice());             }             else             {                 Console.Write("Car Model is not available");             }             Console.ReadLine();         }

After running this application, below is the output

In the above code, we see it is tightly coupled and we can see extra if-else conditions.

Factory Design Pattern Implementation in C#:

 In the Factory pattern, we create product objects without exposing the logic to the end user and we achieve it using the interface

public class CarFactory     {         public static Cars GetCarModelInfo(string CarModelName)         {             Cars carsDetails = null;             if (CarModelName.ToLower() == "honda")             {                 carsDetails = new HondaModelCars();             }             else if (CarModelName.ToLower() == "bmw")             {                 carsDetails = new BMWModelCars();             }             else if (CarModelName.ToLower() == "ferrari")             {                 carsDetails = new FerrariModelCars();             }             return carsDetails;         }     }                            Console.WriteLine("Car Model : " + carsDetails.GetCarModel());                 Console.WriteLine("Car color : " + carsDetails.GetColor());                 Console.WriteLine("Car price :" + carsDetails.GetCarPrice());             }             else             {                 Console.Write("Car Model is not available");             }             Console.ReadLine();         }

 

program.cs class

static void Main(string[] args)         {             Console.WriteLine("Enter the Car Model : ");               string carModel = Console.ReadLine();             Cars carsDetails = CarFactory.GetCarModelInfo(carModel);               if (carsDetails != null)             {                 Console.WriteLine("Car model : " + carsDetails.GetCarModel());                 Console.WriteLine("Car color : " + carsDetails.GetColor());                 Console.WriteLine("Car Price :" + carsDetails.GetCarPrice());             }             else             {                 Console.Write("Invalid Car Model");             }             Console.ReadLine();         }

Author : Dotnet Office | https://www.youtube.com/TheDotNetOffice

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