Show the problem of C # listing 5.10 generated EXE file execution

Problem | execution
Listing 5.10 Gets an IP address through an index

1:using System;
2:using System.Net;
3:
4:class Resolvedns
5: {
6:ipaddress[] m_arrips;
7:
8:public void Resolve (String strhost)
9: {
10:iphostentry Iphe = Dns.gethostbyname (strhost);
11:m_arrips = Iphe. AddressList;
12:}
13:
14:public IPAddress This[int Nindex]
15: {
16:get
17: {
18:return M_arrips[nindex];
19:}
20:}
21st:
22:public int Count
23: {
24:get {return m_arrips.length;}
25:}
26:}
27:
28:class Dnsresolverapp
29: {
30:public static void Main ()
31: {
32:resolvedns mydnsresolver = new Resolvedns ();
33:mydnsresolver.resolve ("http://www.microsoft.com");
34:
35:int ncount = Mydnsresolver.count;
36:console.writeline ("Found {0} IP ' for hostname", ncount);
37:for (int i=0 i < ncount; i++)
38:console.writeline (Mydnsresolver[i]);
39:}
40:}

Compilation Environment:

Visual Studio. NET2003 version 7.1.3091 Microsoft Visual C #. NET

Microsoft. NET Framework version 1.1.4322 SP1

Generated EXE file, error after execution:

An unhandled "System.Net.Sockets.SocketException" type of exception appears in the System.dll.

Additional information: The requested name is valid and were found in the database, but it does not have the correct associated data being re Solved for

What is this for? ......