Multi-parameter indexers in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a multi-parameter indexer in C#?

A multi-parameter indexer allows you to access elements in a class or struct using more than one index value, like accessing a 2D array with two indices.

beginner

How do you declare a multi-parameter indexer in C#?

You declare it by defining an indexer with multiple parameters inside square brackets, for example: <br>public int this[int x, int y] { get { /*...*/ } set { /*...*/ } }

intermediate

Can multi-parameter indexers have different types for each parameter?

Yes, each parameter in a multi-parameter indexer can have a different type, like this[string key, int index].

beginner

What is a practical example of using a multi-parameter indexer?

A common example is a matrix class where you access elements by row and column: <br><code>matrix[row, column]</code>.

intermediate

Can you overload indexers with different numbers of parameters?

Yes, you can have multiple indexers with different parameter counts or types in the same class, allowing different ways to access data.

How do you define a multi-parameter indexer in C#?

A Using multiple parameters inside square brackets in the indexer declaration

B Using multiple indexers with single parameters

C Using a method instead of an indexer

D Using only one parameter but with a tuple type

A multi-parameter indexer is declared by specifying multiple parameters inside the square brackets of the indexer.

Which of these is a valid multi-parameter indexer signature?

A public int this[] { get; set; }

B public int this[int x] { get; set; }

C public int this[int x, int y] { get; set; }

D public int this[int x, int y, int z, int w] { get; set; }

Option C shows a valid multi-parameter indexer with two int parameters.

Can multi-parameter indexers have parameters of different types?

A No, all parameters must be the same type

B Yes, each parameter can have a different type

C Only if they are all numeric types

D Only if they are all reference types

Multi-parameter indexers can have parameters of different types, like string and int.

What is a common use case for multi-parameter indexers?

A Creating single-parameter indexers

B Replacing methods with no parameters

C Declaring properties with multiple values

D Accessing elements in a 2D matrix by row and column

Multi-parameter indexers are often used to access elements in structures like matrices using multiple indices.

Can you overload indexers with different parameter counts in the same class?

A Yes, you can have multiple indexers with different parameters

B No, only one indexer is allowed per class

C Only if they have the same parameter types

D Only if they have the same number of parameters

C# allows overloading indexers with different numbers or types of parameters in the same class.

Explain what a multi-parameter indexer is and give a simple example.

Think about accessing a 2D array with row and column.

Describe how you can overload indexers in a class and why it might be useful.

Consider different ways to access data in the same class.