Indexer In C#

Introduction
C# introduces a new concept known as Indexers which are used for treating an object as an array. The indexers are usually known as smart arrays in C# community. Defining a C# indexer is much like defining properties. We can say that an indexer is a member that enables an object to be indexed in the same way as an array.
{
get
{
// Get codes goes here
}
set
{
// Set codes goes here
}
}
Where the modifier can be private, public, protected or internal. The return type can be any valid C# types. The 'this' is a special keyword in C# to indicate the object of the current class. The formal-argument-list specifies the parameters of the indexer. The formal parameter list of an indexer corresponds to that of a method, except that at least one parameter must be specified, and that the ref and out parameter modifiers are not permitted. Remember that indexers in C# must have at least one parameter. Other wise the compiler will generate a compilation error.
The following program shows a C# indexer in action
using System;
using System.Collections;
class MyClass
{
private string []data = new string[5];
public string this [int index]
{
get
{
return data[index];
}
set
{
data[index] = value;
}
}
}
class MyClient
{
public static void Main()
{
MyClass mc = new MyClass();
mc[0] = "Mithilesh";
mc[1] = "C-125";
mc[2] = "Noida";
mc[3] = "U.P.";
mc[4] = "India";
Console.WriteLine("{0},{1},{2},{3},{4}",mc[0],mc[1],mc[2],mc[3],mc[4]);
}
}

Get Ip Address Of system in Asp.net

public partial class Login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}

protected void Button1_Click(object sender, EventArgs e)
{
Label1.Text = GetIP();
}
private string GetIP()
{
string strHostName = "";
strHostName = System.Net.Dns.GetHostName();

IPHostEntry ipEntry = System.Net.Dns.GetHostEntry(strHostName);

IPAddress[] addr = ipEntry.AddressList;

return addr[addr.Length - 1].ToString();

}
}