Dns.BeginGetHostAddresses(String, AsyncCallback, Object) Method


Asynchronously returns the Internet Protocol (IP) addresses for the specified host.

 static IAsyncResult ^ BeginGetHostAddresses(System::String ^ hostNameOrAddress, AsyncCallback ^ requestCallback, System::Object ^ state);
public static IAsyncResult BeginGetHostAddresses (string hostNameOrAddress, AsyncCallback? requestCallback, object? state);
public static IAsyncResult BeginGetHostAddresses (string hostNameOrAddress, AsyncCallback requestCallback, object state);
static member BeginGetHostAddresses : string * AsyncCallback * obj -> IAsyncResult
Public Shared Function BeginGetHostAddresses (hostNameOrAddress As String, requestCallback As AsyncCallback, state As Object) As IAsyncResult



The host name or IP address to resolve.


An AsyncCallback delegate that references the method to invoke when the operation is complete.


A user-defined object that contains information about the operation. This object is passed to the requestCallback delegate when the operation is complete.


An IAsyncResult instance that references the asynchronous request.


hostNameOrAddress is null.

The length of hostNameOrAddress is greater than 255 characters.

An error is encountered when resolving hostNameOrAddress.

hostNameOrAddress is an invalid IP address.


The BeginGetHostAddresses method asynchronously queries a DNS server for the IP addresses that are associated with a host name. If hostNameOrAddress is an IP address, this address is returned without querying the DNS server.


This member emits trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

If an empty string is passed as the hostNameOrAddress argument, then this method returns the IPv4 and IPv6 addresses of the local host.

The asynchronous BeginGetHostAddresses operation must be completed by calling the EndGetHostAddresses method. Typically, the method is invoked by the requestCallback delegate.

This method does not block until the operation is complete. To block until the operation is complete, use the GetHostAddresses method.

For more information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously

Applies to