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

Recall & Review

beginner

What is a generic method in C#?

A generic method is a method that is declared with type parameters, allowing it to work with any data type while maintaining type safety.

beginner

How do you declare a generic method in C#?

You declare a generic method by adding type parameters in angle brackets after the method name, before the parameter list, like public T Echo<T>(T input).

beginner

Example: What does this method do? public T Echo<T>(T input) { return input; }

This method returns the same value it receives, and it works with any type because of the generic type parameter T.

intermediate

Why use generic methods instead of object type parameters?

Generic methods keep type safety and avoid boxing/unboxing, so the compiler checks types and performance is better.

intermediate

Can generic methods have constraints? Give an example.

Yes, constraints limit the types that can be used. Example: public T CreateInstance<T>() where T : new() { return new T(); } means T must have a parameterless constructor.

How do you declare a generic method in C#?

A Add type parameters in angle brackets after the method name

B Use the keyword 'generic' before the method name

C Declare the method inside a generic class only

D Use 'var' keyword for the method return type

Generic methods declare type parameters in angle brackets after the method name, like .

What is the benefit of using generic methods?

A They make the code run faster by skipping type checks

B They allow working with any data type while keeping type safety

C They only work with reference types

D They replace the need for classes

Generic methods allow any data type but keep type safety checked by the compiler.

Which of these is a valid generic method declaration?

A public GetValue<T>(T value) { return value; }

B public T GetValue(value) { return value; }

C public T GetValue<T>(T value) { return value; }

D public T GetValue<T> { return value; }

Option C correctly declares a generic method with type parameter T.

What does the constraint 'where T : new()' mean in a generic method?

A T must be a reference type

B T must be a value type

C T must inherit from a specific class

D T must have a parameterless constructor

The 'new()' constraint requires T to have a public parameterless constructor.

Can generic methods be declared inside non-generic classes?

A Yes, generic methods can be inside any class

B No, only generic classes can have generic methods

C Only static classes can have generic methods

D Only abstract classes can have generic methods

Generic methods can be declared inside any class, generic or not.

Explain how to declare a generic method in C# and why it is useful.

Think about how you can write one method that works with many types safely.

Describe what constraints are in generic methods and give an example.

Constraints tell the compiler what kind of types can be used.