Indexers (C # Programming Guide)

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Indexers allow instances of a class or struct to be indexed in the same way as an array. Indexers are similar to properties, except that their accessors take parameters.

In the following example, a generic class is defined and a simple get and set accessor method (as a method of assigning and retrieving values) is provided. The program class creates an instance of this class for the storage string.

C#

Class samplecollection<t>{    private t[] arr = new t[100];    Public T This[int i]    {        get        {            return arr[i];        }        Set        {            Arr[i] = value;}}    } This class shows how client code uses the Indexerclass program{    static void Main (string[] args)    {        Sample collection<string> stringcollection = new samplecollection<string> ();        Stringcollection[0] = "Hello, world";        System.Console.WriteLine (Stringcollection[0]);}    }

Indexer Overview

• Indexers enable an object to be indexed in a similar way to an array.

• The get accessor returns a value. The set accessor assigns a value.

• The This keyword is used to define indexers.

• The value keyword is used to define the values assigned by the set indexer.

• Indexers do not have to be indexed by integer values, and you decide how to define a specific lookup mechanism.

• Indexers can be overloaded.

• Indexers can have multiple parameters, such as when accessing a two-dimensional array.

related chapters

• Using Indexers (C # Programming Guide)

• Indexers in Interfaces (C # Programming Guide)

• Comparisons between properties and indexers (C # Programming Guide)

• Asymmetric accessor Accessibility (C # Programming Guide)

• Indexer Sample

• Index Properties sample

Indexers (C # Programming Guide)