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

Recall & Review

beginner

What is an indexer in C#?

An indexer allows an object to be indexed like an array, using square brackets []. It lets you access elements inside an object using an index, just like accessing array elements.

beginner

How do you declare an indexer in a C# class?

You declare an indexer using the keyword this followed by square brackets with a parameter inside. It looks like a property but takes parameters to get or set values.

beginner

What are the two main parts of an indexer declaration?

An indexer has a get accessor to return a value and a set accessor to assign a value, similar to properties.

intermediate

Can indexers have multiple parameters in C#?

Yes, indexers can have multiple parameters, allowing you to index objects with more than one value, like a 2D array.

beginner

What is the return type of an indexer?

The return type of an indexer is specified before the this keyword and defines the type of value the indexer returns or sets.

Which keyword is used to declare an indexer in C#?

A index

B this

C get

D set

The keyword this is used to declare an indexer in C#.

What does the get accessor of an indexer do?

A Returns a value

B Deletes a value

C Declares the indexer

D Assigns a value

The get accessor returns the value at the specified index.

Can an indexer have more than one parameter?

A Yes, multiple parameters are allowed

B No, only one parameter is allowed

C Only if it is static

D Only if it returns void

Indexers can have multiple parameters to support multi-dimensional indexing.

What is the return type of an indexer used for?

A To specify the type of the index

B To specify the access level

C To specify the number of parameters

D To specify the type of value returned or set

The return type defines the type of value the indexer returns or sets.

Which of these is a valid indexer declaration snippet?

A public int this() { get; set; }

B public int indexer(int index) { get; set; }

C public int this[int index] { get { return data[index]; } set { data[index] = value; } }

D public int this[int index] => data[index];

Option C shows a correct indexer with get and set accessors.

Explain how to declare and use an indexer in a C# class.

Think about how you access array elements and how an indexer mimics that.

Describe the purpose and benefits of using indexers in C#.

Why would you want to access an object like an array?