UdpClient Constructor (String, Int32)

Initializes a new instance of the UdpClient class and establishes a default remote host.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

public UdpClient(
	string hostname,
	int port


Type: System.String
The name of the remote DNS host to which you intend to connect.
Type: System.Int32
The remote port number to which you intend to connect.


hostname is null.


port is not between MinPort and MaxPort.


An error occurred when accessing the socket. See the Remarks section for more information.

This constructor initializes a new UdpClient and establishes a remote host using the hostname and port parameters. Establishing a default remote host is optional. If you use this constructor, you do not have to specify a remote host in each call to the Send method. Specifying a default remote host limits you to that host only. You can change the default remote host at any time by calling the Connect method. If you want to specify a remote host in your call to the Send method, do not use this constructor.


If you receive a SocketException, use SocketException.ErrorCode to obtain the specific error code. Once you have obtained this code, you can refer to the Windows Sockets version 2 API error code documentation in MSDN for a detailed description of the error.

The following example demonstrates how to create an instance of the UdpClient class using a host name and port number.

//Creates an instance of the UdpClient class with a remote host name and a port number.
     UdpClient udpClient = new UdpClient("www.contoso.com",11000);
catch (Exception e ) {

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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