Dns.BeginGetHostAddresses(String, AsyncCallback, Object) Method

Definition

Namespace:

System.Net

Assembly:

System.Net.NameResolution.dll

Source:

Dns.cs

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

public:
 static IAsyncResult ^ BeginGetHostAddresses(System::String ^ hostNameOrAddress, AsyncCallback ^ requestCallback, System::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

Parameters

hostNameOrAddress

String

The host name or IP address to resolve.

requestCallback

AsyncCallback

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

state

Object

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

Returns

IAsyncResult

An IAsyncResult instance that references the asynchronous request.

Exceptions

ArgumentNullException

hostNameOrAddress is null.

ArgumentOutOfRangeException

The length of hostNameOrAddress is greater than 255 characters.

SocketException

An error is encountered when resolving hostNameOrAddress.

ArgumentException

hostNameOrAddress is an invalid IP address.

Remarks

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.

Note

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