C# Abstract Classes Explained: Practical Examples, Patterns, and Best Practices
TL;DR: Abstract Class in C# - TL;DR What Is Abstract Class? Definition: Incomplete class that cannot be instantiated directly Purpose: Blueprint for related classes with shared behavior Keywords: abstract class, abstract methods, override in derived classes Key Features Mixed Implementation: Can have both concrete methods and abstract methods State: Can contain fields, properties, constructors Access Modifiers: Supports private, protected, internal members Inheritance: Single inheritance only Abstract vs Virtual Methods Abstract: No implementation, must be overridden Virtual: Has default implementation, can be overridden Regular: Concrete implementation, cannot be overridden When to Use Abstract Classes Share code between related classes Need constructors or protected members Template method pattern (define workflow, customize steps) Enforce implementation while providing base functionality Limitations of Abstract Classes Cannot be instantiated directly Single inheritance only Cannot be sealed Common Use Cases Framework/SDK base classes Database providers Document processors Any scenario needing shared behavior + enforced implementation Picture this: you’re building a document management system where users can create Word documents, PDFs, and Excel files. Each document type has its own specific formatting and processing logic, but they all share common behaviors, they need to be saved, validated, and have metadata tracked. ...