/// <summary>Asynchronously resolves a host name or IP address to an <see cref="T:System.Net.IPHostEntry" /> instance.</summary>
/// <returns>An <see cref="T:System.IAsyncResult" /> instance that references the asynchronous request.</returns>
/// <param name="hostNameOrAddress">The host name or IP address to resolve.</param>
/// <param name="requestCallback">An <see cref="T:System.AsyncCallback" /> delegate that references the method to invoke when the operation is complete. </param>
/// <param name="stateObject">A user-defined object that contains information about the operation. This object is passed to the <paramref name="requestCallback" /> delegate when the operation is complete.</param>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="hostNameOrAddress" /> is null. </exception>
/// <exception cref="T:System.ArgumentOutOfRangeException">The length of <paramref name="hostNameOrAddress" /> is greater than 126 characters. </exception>
/// <exception cref="T:System.Net.Sockets.SocketException">An error is encountered when resolving <paramref name="hostNameOrAddress" />. </exception>
/// <exception cref="T:System.ArgumentException">
/// <paramref name="hostNameOrAddress" /> is an invalid IP address.</exception>
public static IAsyncResult BeginGetHostEntry(string hostNameOrAddress, AsyncCallback requestCallback, object stateObject)
{
if (hostNameOrAddress == null)
{
throw new ArgumentNullException("hostName");
}
if (hostNameOrAddress == "0.0.0.0" || hostNameOrAddress == "::0")
{
throw new ArgumentException("Addresses 0.0.0.0 (IPv4) and ::0 (IPv6) are unspecified addresses. You cannot use them as target address.", "hostNameOrAddress");
}
Dns.GetHostEntryNameCallback getHostEntryNameCallback = new Dns.GetHostEntryNameCallback(Dns.GetHostEntry);
return(getHostEntryNameCallback.BeginInvoke(hostNameOrAddress, requestCallback, stateObject));
}
/// <summary>Ends an asynchronous request for DNS information.</summary>
/// <returns>An <see cref="T:System.Net.IPHostEntry" /> instance that contains address information about the host.</returns>
/// <param name="asyncResult">An <see cref="T:System.IAsyncResult" /> instance returned by a call to an <see cref="Overload:System.Net.Dns.BeginGetHostEntry" /> method.</param>
/// <exception cref="T:System.ArgumentNullException">
/// <paramref name="asyncResult" /> is null. </exception>
public static IPHostEntry EndGetHostEntry(IAsyncResult asyncResult)
{
if (asyncResult == null)
{
throw new ArgumentNullException("asyncResult");
}
AsyncResult asyncResult2 = (AsyncResult)asyncResult;
if (asyncResult2.AsyncDelegate is Dns.GetHostEntryIPCallback)
{
return(((Dns.GetHostEntryIPCallback)asyncResult2.AsyncDelegate).EndInvoke(asyncResult));
}
Dns.GetHostEntryNameCallback getHostEntryNameCallback = (Dns.GetHostEntryNameCallback)asyncResult2.AsyncDelegate;
return(getHostEntryNameCallback.EndInvoke(asyncResult));
}
