Dns.BeginGetHostEntry Method (IPAddress, AsyncCallback, Object)
Asynchronously resolves an IP address to an IPHostEntry instance.
Namespace: System.Net
Assembly: System (in System.dll)
[<HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)>] static member BeginGetHostEntry : address:IPAddress * requestCallback:AsyncCallback * stateObject:Object -> IAsyncResult
Parameters
- address
- Type: System.Net.IPAddress
The IP address to resolve.
- requestCallback
- Type: System.AsyncCallback
An AsyncCallback delegate that references the method to invoke when the operation is complete.
- stateObject
- Type: System.Object
A user-defined object that contains information about the operation. This object is passed to the requestCallback delegate when the operation is complete.
Return Value
Type: System.IAsyncResultAn IAsyncResult instance that references the asynchronous request.
| Exception | Condition |
|---|---|
| ArgumentNullException | address is a null reference (Nothing in Visual Basic). |
| SocketException | An error is encountered when resolving address. |
| ArgumentException | address is an invalid IP address. |
The BeginGetHostEntry method asynchronously queries a DNS server for the IP addresses and aliases associated with an IP address.
Note This member emits trace information when you enable network tracing in your application. For more information, see Network Tracing.
The asynchronous BeginGetHostEntry operation must be completed by calling the EndGetHostEntry 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 GetHostEntry method.
For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously
.gif?cs-save-lang=1&cs-lang=fsharp "Note") Note |
|---|
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: ExternalThreading. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
The following code example uses the BeginGetHostEntry method to resolve an IP address to an IPHostEntry instance.
- DnsPermission
for accessing DNS information. Associated enumeration: PermissionState.Unrestricted
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
