SOLID Design Principles in C#

SOLID Design Principles in C# with Real-Time Examples

In this SOLID Design Principles in C# with Examples article series, I am going to discuss the examples by taking some real-time scenarios using different types of .NET Applications which include ASP.NET MVC, Web API, and Console Applications.

The SOLID Design Principles in C# are the design principles that help us to solve most of the software design problems. These design principles provide us with multiple ways to remove the tightly coupled code between the software components (between classes) which makes the software designs more understandable, more flexible, and more maintainable. 

This SOLID Design Principles Course is For whom:

This course is designed for Students, Beginners as well as Professionals Software Developers who want to learn SOLID Design Principles using C# Language step by step with Real-Time Examples. This tutorial provides you with a hands-on approach to the subject with step-by-step programming examples that will assist you to learn and put the acquired knowledge into practice.

Why Do We Need to Learn SOLID Design Principles?

As a developer, we start developing applications using our experience and knowledge. But over time, the applications might arise bugs. We need to alter the application design for every change request or for a new feature request. After some time we might need to put in a lot of effort, even for simple tasks, it might require the full working knowledge of the entire system. But we can’t blame the change request or new feature requests as they are part of the software development. We can’t stop them and we can’t refuse them either. So who is the culprit here? Obviously, it is the Design of the Application.

So, by considering the above problem and helping Students, Beginners as well as Professionals Software Developers who want to learn How to design good software using SOLID Design Principles using C# Language in a quick time, I have decided to start a series of articles on SOLID Design Principles with Real-time Examples.

Advantages of SOLID Design Principles in C#

As a developer, while you are designing and developing any software applications, then you need to consider the following points.

• Maintainability: Nowadays maintaining the software is the biggest challenge for the Industry. Day by day the business grows for the organization and as the business grows you need to enhance the software with new changes or with existing feature modifications or enhancements. So, you need to design the software in such a way that it should accept future changes and existing feature modifications or enhancements with minimum effort and without any problem.
• Testability: Test-Driven Development (TDD) is one of the most important key aspects nowadays when you need to design and develop a large-scale application. We need to design the application in such a way that we should test each individual functionality. 
• Flexibility and Extensibility: Nowadays flexibility and extensibility are very much required for enterprise applications. So we should design the application in such a way that it should be flexible so that it can be adapted to work in different ways and extensible so that we can add new features easily with minimum modifications.
• Parallel Development: The Parallel Development of an application is one of the most important key aspects. As we know it is not possible to have the entire development team will work on the same module at the same time. So we need to design the software in such a way that different teams can work on different modules of the project.

The SOLID Design Principles and Design Patterns play an important role in achieving all of the above key points.

What are the Main Reasons Behind for Most Unsuccessful Applications?

The following are the Main Reasons Behind Most Unsuccessful Applications.

1. Putting More Functionalities on Classes. (In simple words a lot of functionalities we are putting into the class even though they are not related to that class.)
2. Implementing Tight Coupling Between the Software Components (i.e. Between the Classes). If the classes are dependent on each other, then a change in one class will affect the other classes also.

How to Overcome the Unsuccessful Application Development Problems?

1. We need to use the Correct Architecture (i.e. MVC, Layered, 3-Tier, MVP, and so on) as per the Project Requirements.
2. As a developer, we need to follow the Design Principles (i.e. SOLID Principles, ONIO Design Principles, etc.).
3. Again we need to choose the correct Design Patterns (Creational Design Pattern,  Structural Design Pattern, Behavioral Design Pattern, Dependency Injection Design Pattern, Repository Design Pattern, etc.) as per the project requirements.

What are SOLID Design Principles?

The SOLID Design Principles are the Design Principles basically used to manage most of the Software Design Problems that generally we as a developer encountered in our day-to-day programming. These design principles are tested and proven mechanisms that will make the software designs more understandable, more flexible, and more maintainable. As a result, if we follow these principles while designing our application, then we can develop better applications.

SOLID Design Principles represent five Design Principles that basically used to make software designs more understandable, more flexible, and more maintainable. The Five SOLID Design Principles are as follows:

1. S stands for the Single Responsibility Principle which is also known as SRP: The Single Responsibility Principle in C# states that Each software module or class should have only one reason to change. In other words, we can say that each module or class should have only one responsibility to do.
2. O stands for the Open-Closed Principle which is also known as OSP: The Open-Closed Principle states that software entities such as modules, classes, functions, etc. should be open for extension, but closed for modification.
3. L stands for the Liskov Substitution Principle which is also known as LSP: The Liskov Substitution Principle says that the object of a derived class should be able to replace an object of the base class without bringing any errors in the system or modifying the behavior of the base class. That means child class objects should be able to replace parent class objects without compromising application integrity.
4. I stand for the Interface Segregation Principle which is also known as ISP: The Interface Segregation Principle states that Clients should not be forced to implement any methods they don’t use. Rather than one fat interface, numerous little interfaces are preferred based on groups of methods with each interface serving one submodule.
5. D stands for Dependency Inversion Principle which is also known as DIP: The Dependency Inversion Principle (DIP) states that high-level modules/classes should not depend on low-level modules/classes. Both should depend upon abstractions. Secondly, abstractions should not depend upon details. Details should depend upon abstractions.

What are the Advantages of using SOLID Design Principles in C#?

We will get the following advantages by using SOLID Design Principles in C#.

1. It will reduce the Complexity of the Application Code
2. It will Increase readability and extensibility, and we can easily maintain the application 
3. Reduce Error and Implement Reusability
4. Achieve Better Testability
5. Reduce Tight Coupling

In this article series, I am going to cover all the features of SOLID Design Principles in C# with real-time examples. You will learn from the basic to advance level features of SOLID Design Principles in C# with Real-time Examples as we progress.