What are some examples of constraints in C# generics?

What are some examples of constraints in C# generics?

In C#, constraints are used to specify the requirements for the types that can be used as type arguments in generics. For example, you can use the where keyword to enforce that a type must implement a specific interface or inherit from a certain class.

Can you give me a specific example of a constraint?

Sure! For instance, if you have a generic class Repository<T>, you can constrain T to be a class that implements an interface IEntity like this: where T : IEntity. This ensures that only types implementing IEntity can be used with Repository.

What happens if I try to use a type that doesn't meet the constraint?

If you try to use a type that doesn't meet the constraint, you'll get a compile-time error. The compiler checks the constraints and ensures that the type arguments provided satisfy them.

Are there different types of constraints I can use?

Yes, there are several types of constraints you can use, such as where T : class for reference types, where T : struct for value types, and where T : new() to require a parameterless constructor.