Dns.BeginGetHostEntry Method (String, AsyncCallback, Object)

'Declaration
Public Shared Function BeginGetHostEntry ( _
	hostNameOrAddress As String, _
	requestCallback As AsyncCallback, _
	stateObject As Object _
) As IAsyncResult
'Usage
Dim hostNameOrAddress As String
Dim requestCallback As AsyncCallback
Dim stateObject As Object
Dim returnValue As IAsyncResult

returnValue = Dns.BeginGetHostEntry(hostNameOrAddress, requestCallback, stateObject)

public static IAsyncResult BeginGetHostEntry (
	String hostNameOrAddress, 
	AsyncCallback requestCallback, 
	Object stateObject
)

public static function BeginGetHostEntry (
	hostNameOrAddress : String, 
	requestCallback : AsyncCallback, 
	stateObject : Object
) : IAsyncResult

// Signals when the resolve has finished.
public static ManualResetEvent GetHostEntryFinished = 
    new ManualResetEvent(false);

// Define the state object for the callback. 
// Use hostName to correlate calls with the proper result.
public class ResolveState
{
    string hostName;
    IPHostEntry resolvedIPs;

    public ResolveState(string host)
    {
        hostName = host;
    }

    public IPHostEntry IPs
    {
        get { return resolvedIPs; } 
        set {resolvedIPs = value;}}
    public string host {get {return hostName;} 
        set {hostName = value;}}
}

// Record the IPs in the state object for later use.
public static void GetHostEntryCallback(IAsyncResult ar)
{
    ResolveState ioContext = (ResolveState)ar.AsyncState;

    ioContext.IPs = Dns.EndGetHostEntry(ar);
    GetHostEntryFinished.Set();
}       

// Determine the Internet Protocol (IP) addresses for 
// this host asynchronously.
public static void DoGetHostEntryAsync(string hostname)
{
    GetHostEntryFinished.Reset();
    ResolveState ioContext= new ResolveState(hostname);

    Dns.BeginGetHostEntry(ioContext.host, 
        new AsyncCallback(GetHostEntryCallback), ioContext);

    // Wait here until the resolve completes (the callback 
    // calls .Set())
    GetHostEntryFinished.WaitOne();

    Console.WriteLine("EndGetHostEntry({0}) returns:", ioContext.host);

    foreach (IPAddress ip in ioContext.IPs.AddressList)
    {
        Console.WriteLine("    {0}", ip);
    }
 
}