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May 11, 2011
- An indexer allows programmer to create classes that can act like VIRTUAL ARRAYS.
- We can access instances of those classes using the [] array access operator.
- Defining an indexer in C#.net is similar to defining operator [] in C++, but it is considerably more flexible in .Net.
- An indexer can have private, public, protected or internal modifier & the return type can be any valid C# types.
- Use of an indexer allows the user or programmer of that class which encapsulate array or collection like functionality
to use the array syntax to access the class.
- An Indexer in C#.Net must have at least one parameter otherwise the compiler will throw a compilation error.
class Codekey_Indexer_Class
{
private int[] expArray = new int[50];
public int this[int index]
{
get
{
if (index < 0 || index >= 50)
return 0;
else
return expArray[index];
}
set
{
if (!(index < 0 || index >= 50))
expArray[index] = value;
}
}
}
public class Codekey_Main_Class
{
public static void Main(string[] args)
{
Codekey_Indexer_Class b = new Codekey_Indexer_Class();
b[3] = 420;
b[5] = 840;
for (int k = 1; k <= 5; k++)
{
Console.WriteLine("Value of #{0} is = {1}", k, b[k]);
}
}
}
Output:
Value of #1 is = 0
Value of #2 is = 0
Value of #3 is = 420
Value of #4 is = 0
Value of #5 is = 840
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