rohit

• Nov 18th, 2005

 

6546

Vamsi Chunduru

 Profile Answers by Vamsi Chunduru 

• Apr 12th, 2006

 

Indexer is a special syntax for overloading [] operator for a class. After defining an indexer, array syntaxes can be used for the class objects.

madhavi

• Nov 14th, 2006

 

Indexers 

Indexers permit instances of a class or struct to be indexed in the same way as arrays. Indexers are similar to propeties except that their accessors take parameters.

In the following example, a generic class is defined and provided with simple get and set accessor methods as a means for assigning and retrieving values. The class Program creates an instance of this class for storing strings.

public class IndexerClass

{

private int[] arr = new int[100];

public int this[int index]

{

get

{

if (index < 0 || index >= 100)

return 0;

else

return arr[index];

}

set

{

if (!(index < 0 || index >= 100))

{

arr[index] = value;

}

}

}

static void Main(string[] args)

{

IndexerClass ic = new IndexerClass();

ic[1] = 10;

ic[2] = 20;

for (int i = 0; i <= 10; i++)

{

System.Console.WriteLine("Element #{0} = {1}", i, ic[i]);

}

Console.Read();

}

}

• Indexers enable objects to be indexed in a similar way to arrays.

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

• The this keyword is used to define the indexers.

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

• Indexers do not have to be indexed by an integer value; it is up to you how to define the specific look-up mechanism.

• Indexers can be overloaded.

• Indexers can have more than one formal parameter, for example, when accessing a two-dimensional array.

For more information Click here http://msdn2.microsoft.com/en-us/library/2549tw02.aspx