/// <summary>
/// Handle the async DNS response.
/// </summary>
/// <param name="ar"></param>
private void OnResolved(IAsyncResult ar)
{
try
{
IPHostEntry ent = Dns.EndGetHostEntry(ar);
if (ent.AddressList.Length <= 0)
{
m_ip = null;
}
else
{
// From docs:
// When hostName is a DNS-style host name associated with multiple IP addresses,
// only the first IP address that resolves to that host name is returned.
m_ip = ent.AddressList[0];
}
}
catch (Exception e)
{
Debug.WriteLine(e.ToString());
m_ip = null;
}
AddressResolved callback = (AddressResolved)ar.AsyncState;
if (callback != null)
{
callback(this);
}
}
/// <summary>
/// Async DNS lookup. IP will be null in callback on failure. Callback will
/// be called immediately if IP is already known (e.g. dotted-quad).
/// </summary>
/// <param name="callback">Called when resolution complete.</param>
public void Resolve(AddressResolved callback)
{
if ((m_ip != null) && (m_ip != IPAddress.Any) &&
(m_ip != IPAddress.IPv6Any)
)
{
callback(this);
}
else
{
Dns.BeginGetHostEntry(m_hostname, new AsyncCallback(OnResolved), callback);
}
}
/// <summary>
/// Async DNS lookup. IP will be null in callback on failure. Callback will
/// be called immediately if IP is already known (e.g. dotted-quad).
/// </summary>
/// <param name="callback">Called when resolution complete.</param>
public void Resolve(AddressResolved callback)
{
if ((m_ip != null) && (m_ip != IPAddress.Any)
&& (m_ip != IPAddress.IPv6Any)
)
{
callback(this);
}
else
Dns.BeginGetHostEntry(m_hostname, new AsyncCallback(OnResolved), callback);
}