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Socket Constructor (AddressFamily, SocketType, ProtocolType)

Initializes a new instance of the Socket class using the specified address family, socket type and protocol.

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

Public Sub New ( _
	addressFamily As AddressFamily, _
	socketType As SocketType, _
	protocolType As ProtocolType _


Type: System.Net.Sockets.AddressFamily
One of the AddressFamily values.
Type: System.Net.Sockets.SocketType
One of the SocketType values.
Type: System.Net.Sockets.ProtocolType
One of the ProtocolType values.


The combination of addressFamily, socketType, and protocolType results in an invalid socket.

The addressFamily parameter specifies the addressing scheme that the Socket class uses, the socketType parameter specifies the type of the Socket class, and the protocolType parameter specifies the protocol used by Socket. The three parameters are not independent. Some address families restrict which protocols can be used with them, and often the Socket type is implicit in the protocol. If the combination of address family, Socket type, and protocol type results in an invalid Socket, this constructor throws a SocketException.


If this constructor throws a SocketException, use the SocketException.ErrorCode property to obtain the specific error code. After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation in the MSDN library for a detailed description of the error.


This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following code example demonstrates how to create an instance of the Socket class.

Imports System
Imports System.Text
Imports System.IO
Imports System.Net
Imports System.Net.Sockets


Public Class Sample

   Public Shared Function DoSocketGet(server As String) As String
      'Set up variables and String to write to the server.
    Dim ASCII As Encoding = Encoding.ASCII
    Dim [Get] As String = "GET / HTTP/1.1" + ControlChars.Lf + ControlChars.NewLine + "Host: " + server + ControlChars.Lf + ControlChars.NewLine + "Connection: Close" + ControlChars.Lf + ControlChars.NewLine + ControlChars.Lf + ControlChars.NewLine
    Dim ByteGet As [Byte]() = ASCII.GetBytes([Get])
    Dim RecvBytes(256) As [Byte]
    Dim strRetPage As [String] = Nothing

      ' IPAddress and IPEndPoint represent the endpoint that will
      '   receive the request.
      ' Get first IPAddress in list return by DNS.

         ' Define those variables to be evaluated in the next for loop and 
         ' then used to connect to the server. These variables are defined
         ' outside the for loop to make them accessible there after.
         Dim s As Socket = Nothing
         Dim hostEndPoint As IPEndPoint
         Dim hostAddress As IPAddress = Nothing
         Dim conPort As Integer = 80

         ' Get DNS host information.
         Dim hostInfo As IPHostEntry = Dns.Resolve(server)
         ' Get the DNS IP addresses associated with the host.
         Dim IPaddresses As IPAddress() = hostInfo.AddressList

         ' Evaluate the socket and receiving host IPAddress and IPEndPoint. 
      Dim index As Integer = 0
      For index = 0 To IPaddresses.Length - 1
        hostAddress = IPaddresses(index)
        hostEndPoint = New IPEndPoint(hostAddress, conPort)

        ' Creates the Socket to send data over a TCP connection.
        s = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)

        ' Connect to the host using its IPEndPoint.

        If Not s.Connected Then
          ' Connection failed, try next IPaddress.
          strRetPage = "Unable to connect to host"
          s = Nothing
          GoTo ContinueFor1
        End If

        ' Sent the GET request to the host.
        s.Send(ByteGet, ByteGet.Length, 0)

      Next index  ' End of the for loop.

      ' Receive the host home page content and loop until all the data is received.

      'Dim bytes As Int32 = s.Receive(RecvBytes, RecvBytes.Length, 0)
      Dim bytes As Int32 = s.Receive(RecvBytes, RecvBytes.Length, 0)

      strRetPage = "Default HTML page on " + server + ":\r\n"
      strRetPage = "Default HTML page on " + server + ":" + ControlChars.Lf + ControlChars.NewLine

      Dim i As Integer

      While bytes > 0

        bytes = s.Receive(RecvBytes, RecvBytes.Length, 0)

        strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes)

      End While

      ' End of the try block.
    Catch e As SocketException
         Console.WriteLine("SocketException caught!!!")
         Console.WriteLine(("Source : " + e.Source))
         Console.WriteLine(("Message : " + e.Message))
      Catch e As ArgumentNullException
         Console.WriteLine("ArgumentNullException caught!!!")
         Console.WriteLine(("Source : " + e.Source))
         Console.WriteLine(("Message : " + e.Message))
      Catch e As NullReferenceException
         Console.WriteLine("NullReferenceException caught!!!")
         Console.WriteLine(("Source : " + e.Source))
         Console.WriteLine(("Message : " + e.Message))
      Catch e As Exception
         Console.WriteLine("Exception caught!!!")
         Console.WriteLine(("Source : " + e.Source))
         Console.WriteLine(("Message : " + e.Message))
      End Try

      Return strRetPage
   End Function 'DoSocketGet

   Public Shared Sub Main()
   End Sub 'Main
End Class 'Sample

.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.