DESIGN PATTERNS SERIES

How to Switch the Algorithms at Runtime with Strategy Pattern in C#

When, Why, and How to use Strategy Pattern in C#. The quick and easy introduction.

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The Strategy Pattern

Strategy Pattern or SP enables selecting an algorithm at runtime. Simply said, we choose an algorithm based on the incoming dynamic parameter.

Sounds like decision-statement, right? Switching an algorithm based on parameter value? We are talking about a switch or if-else statements, correct?

Well, yes. SP is some kind of decision-statement. But SP follows rules of Object-oriented programming languages and brings theirs advantages to the table like reusability and extensibility. It also meets the requirements of the SOLID code.

Advantages of the Strategy Pattern

• It’s easy to switch between different algorithms (strategies) in runtime because you’re using polymorphism in the interfaces.
• Clean code because you avoid decision-statements (not complicated).
• More clean code because you separate the concerns into classes (a class to each Strategy).
• Decoupled and easily testable code.