Generic interfaces in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a generic interface in C#?

A generic interface is an interface that has one or more type parameters. It allows you to define methods and properties that work with any data type specified when the interface is implemented.

beginner

How do you declare a generic interface with one type parameter named T?

You declare it like this: <br>

public interface IExample<T> {<br>    void DoSomething(T item);<br>}

intermediate

Why use generic interfaces instead of non-generic ones?

Generic interfaces provide type safety and code reuse. They let you write flexible code that works with any data type without losing the benefits of compile-time type checking.

beginner

How do you implement a generic interface in a class?

You specify the type when implementing the interface. For example:<br><pre>public class MyClass : IExample&lt;int&gt; {<br>    public void DoSomething(int item) {<br>        // implementation<br>    }<br>}</pre>

intermediate

Can a generic interface have multiple type parameters? Give an example.

Yes, it can. Example:<br>

public interface IPair<T1, T2> {<br>    T1 First { get; }<br>    T2 Second { get; }<br>}

What does the <T> mean in a generic interface declaration?

A It is a placeholder for a data type specified later

B It is a method name

C It is a variable

D It is a keyword to create an object

The <T> is a placeholder for a type that will be specified when the interface is implemented.

How do you specify the type when implementing a generic interface?

A By providing the type in angle brackets after the interface name

B By declaring a new interface

C By using the 'new' keyword

D By casting the interface

You specify the type by writing the interface name followed by the type in angle brackets, like IExample.

Which of these is a valid generic interface declaration?

A public interface ITest { void Do(T item); }

B public class ITest<T> { void Do(T item); }

C public interface ITest<T> { void Do(T item); }

D public interface ITest<T> { T Do(); }

Option C correctly declares a generic interface with a method using the generic type T.

Can a generic interface have properties using the generic type?

A Only static properties can use the generic type

B Yes, properties can use the generic type

C No, generic interfaces cannot have properties

D No, only methods can use the generic type

Generic interfaces can have properties that use the generic type parameter.

What is the main advantage of using generic interfaces?

A They allow private methods in interfaces

B They make code run faster

C They reduce the number of classes needed

D They allow code reuse with type safety

Generic interfaces allow writing reusable code that works with any type while keeping type safety.

Explain what a generic interface is and why it is useful.

Think about how you can write one interface that works with many data types.

Describe how to implement a generic interface in a class with an example.

Remember to specify the type in angle brackets after the interface name.