Decoupling Logic with the Strategy Pattern in C#

How to Implement the Strategy Pattern in C#

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The Strategy Design Pattern is a behavioral design pattern that allows selecting an algorithm at runtime from a family of algorithms. It helps in creating flexible and reusable code by encapsulating algorithms separately and making them interchangeable without modifying the existing code structure.

Problem Without Strategy Pattern

Without the Strategy Pattern, we often use conditional statements (if-else or switch-case) to decide which algorithm or method to use. This leads to:

1. Code Duplication — Multiple conditional checks across different parts of the codebase.
2. Difficult Maintenance — Adding a new strategy requires modifying existing code.
3. Violation of Open/Closed Principle — The class needs modification whenever a new algorithm is introduced.
4. Lack of Reusability — Algorithms are tightly coupled with the class using them.

Example Without Strategy Pattern

using System;

public class PaymentService
{
    public void ProcessPayment(string paymentType)
    {
        if (paymentType == "CreditCard")
        {…