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Socket Constructor

.NET Framework 1.1

Initializes a new instance of the Socket class.

[Visual Basic]
Public Sub New( _
   ByVal addressFamily As AddressFamily, _
   ByVal socketType As SocketType, _
   ByVal protocolType As ProtocolType _
)
[C#]
public Socket(
   AddressFamily addressFamily,
 SocketType socketType,
 ProtocolType protocolType
);
[C++]
public: Socket(
   AddressFamily addressFamily,
 SocketType socketType,
 ProtocolType protocolType
);
[JScript]
public function Socket(
   addressFamily : AddressFamily,
 socketType : SocketType,
 protocolType : ProtocolType
);

Parameters

addressFamily
One of the AddressFamily values.
socketType
One of the SocketType values.
protocolType
One of the ProtocolType values.

Exceptions

Exception Type Condition
SocketException The combination of addressFamily, socketType, and protocolType results in an invalid socket.

Remarks

The addressFamily parameter specifies the addressing scheme that the Socket uses, the socketType parameter specifies the type of the Socket, and the protocolType parameter specifies the protocol used by the 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 will throw a SocketException.

Note   If this constructor throws a SocketException, use SocketException.ErrorCode to obtain the specific error code. Once you have obtained this code, you can refer to the Windows Socket Version 2 API error code documentation in MSDN for a detailed description of the error.

Example

[Visual Basic, C#, C++] The following example demonstrates how to create an instance of the Socket class.

[Visual Basic] 
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.
      Try

 

         ' 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.
        s.Connect(hostEndPoint)

        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)


ContinueFor1:
      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()
    Console.WriteLine(DoSocketGet("localhost"))
   End Sub 'Main
End Class 'Sample

[C#] 
using System;
using System.Text;
using System.IO;
using System.Net;
using System.Net.Sockets;

public class Sample
{

  public static string DoSocketGet(string server) 
  {
    //Set up variables and String to write to the server.
    Encoding ASCII = Encoding.ASCII;
    string Get = "GET / HTTP/1.1\r\nHost: " + server + 
                 "\r\nConnection: Close\r\n\r\n";
    Byte[] ByteGet = ASCII.GetBytes(Get);
    Byte[] RecvBytes = new Byte[256];
    String strRetPage = null;


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


    try
    {


      // 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.
      Socket s = null;
      IPEndPoint hostEndPoint;
      IPAddress hostAddress = null;
      int conPort = 80;

      // Get DNS host information.
      IPHostEntry hostInfo = Dns.Resolve(server);
      // Get the DNS IP addresses associated with the host.
      IPAddress[] IPaddresses = hostInfo.AddressList;

      // Evaluate the socket and receiving host IPAddress and IPEndPoint. 
      for (int index=0; index<IPaddresses.Length; index++)
      {
        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.
        s.Connect(hostEndPoint);

        if (!s.Connected)
        {
          // Connection failed, try next IPaddress.
          strRetPage = "Unable to connect to host";
          s = null;
          continue;
        }

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


      } // End of the for loop.      


 
      // Receive the host home page content and loop until all the data is received.
      Int32 bytes = s.Receive(RecvBytes, RecvBytes.Length, 0);
      strRetPage = "Default HTML page on " + server + ":\r\n";
      strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
 
      while (bytes > 0)
      {
        bytes = s.Receive(RecvBytes, RecvBytes.Length, 0);
        strRetPage = strRetPage + ASCII.GetString(RecvBytes, 0, bytes);
      }

    
    } // End of the try block.
    
    catch(SocketException e) 
    {
      Console.WriteLine("SocketException caught!!!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
    catch(ArgumentNullException e)
    {
      Console.WriteLine("ArgumentNullException caught!!!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
    catch(NullReferenceException e)
    {
      Console.WriteLine("NullReferenceException caught!!!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
    catch(Exception e)
    {
      Console.WriteLine("Exception caught!!!");
      Console.WriteLine("Source : " + e.Source);
      Console.WriteLine("Message : " + e.Message);
    }
    
    return strRetPage;

}
   public static void Main()
   {
      Console.WriteLine(DoSocketGet("localhost"));
   }
 }

[C++] 
#using <mscorlib.dll>
#using <System.dll>

using namespace System;
using namespace System::Text;
using namespace System::IO;
using namespace System::Net;
using namespace System::Net::Sockets;

String *DoSocketGet(String *server) 
{
   //Set up variables and String to write to the server.
   Encoding *ASCII = Encoding::ASCII;
   String *Get = "GET / HTTP/1.1\r\nHost: ";
   Get->Concat(server, "\r\nConnection: Close\r\n\r\n");
   Byte ByteGet[] = ASCII->GetBytes(Get);
   Byte RecvBytes[] = new Byte[256];
   String *strRetPage = 0;

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

   try
   {
      // 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.
      Socket *s = 0;
      IPEndPoint *hostEndPoint;
      IPAddress *hostAddress = 0;
      int conPort = 80;

      // Get DNS host information.
      IPHostEntry *hostInfo = Dns::Resolve(server);
      // Get the DNS IP addresses associated with the host.
      IPAddress *IPaddresses[] = hostInfo->AddressList;

      // Evaluate the socket and receiving host IPAddress and IPEndPoint. 
      for (int index=0; index<IPaddresses->Length; index++)
      {
         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.
         s->Connect(hostEndPoint);

         if (!s->Connected)
         {
            // Connection failed, try next IPaddress.
            strRetPage = "Unable to connect to host";
            s = 0;
            continue;
         }

         // Sent the GET request to the host.
         s->Send(ByteGet, ByteGet->Length, SocketFlags::None);


      } // End of the for loop.      



      // Receive the host home page content and loop until all the data is received.
      Int32 bytes = s->Receive(RecvBytes, RecvBytes->Length, SocketFlags::None);
      strRetPage = "Default HTML page on ";
      strRetPage->Concat(server, ":\r\n", ASCII->GetString(RecvBytes, 0, bytes));

      while (bytes > 0)
      {
         bytes = s->Receive(RecvBytes, RecvBytes->Length, SocketFlags::None);
         strRetPage->Concat(ASCII->GetString(RecvBytes, 0, bytes));
      }


   } // End of the try block.

   catch(SocketException *e) 
   {
      Console::WriteLine("SocketException caught!!!");
      Console::Write("Source : ");
      Console::WriteLine(e->Source);
      Console::Write("Message : ");
      Console::WriteLine(e->Message);
   }
   catch(ArgumentNullException *e)
   {
      Console::WriteLine("ArgumentNULLException caught!!!");
      Console::Write("Source : ");
      Console::WriteLine(e->Source);
      Console::Write("Message : ");
      Console::WriteLine(e->Message);
   }
   catch(NullReferenceException *e)
   {
      Console::WriteLine("NULLReferenceException caught!!!");
      Console::Write("Source : ");
      Console::WriteLine(e->Source);
      Console::Write("Message : ");
      Console::WriteLine(e->Message);
   }
   catch(Exception *e)
   {
      Console::WriteLine("Exception caught!!!");
      Console::Write("Source : ");
      Console::WriteLine(e->Source);
      Console::Write("Message : ");
      Console::WriteLine(e->Message);
   }

   return strRetPage;
}

int main()
{
   Console::WriteLine(DoSocketGet("localhost"));
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

Socket Class | Socket Members | System.Net.Sockets Namespace | SocketException | AddressFamily | ProtocolType | SocketType

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