Generics

Overview

Generics in C# allow for the creation of reusable classes, structures, methods, delegates, and interfaces with placeholder types.

Key Points

• Reusability: Generics provide reusability through a “template” that contains “placeholder” types.
• Covariance: Generic types are not covariant. This means that even if type B can be cast to type A, T<B> cannot be cast to T<A>.
• Constraints: There are three kinds of constraints in generics – derivation constraint, constructor constraint, and reference/value constraint.
• Derivation Constraint: In the derivation constraint, the base constrained type must never have lower visibility than the generic type parameter.
• Constraint Order: The order of constraints is important and should be followed as follows:
  1. Reference/Value Constraint
  2. Derivation Constraint
  3. Constructor Constraint

Example

            public class Example<T>
            {
                public T Value { get; set; }

                public Example(T value)
                {
                    Value = value;
                }
            }
        

Conclusion

Understanding generics in C# is crucial for creating flexible and reusable code. By leveraging generics, developers can write more efficient and maintainable code that can work with a variety of data types.