VB.NET Socket編程實際操作方法介紹

作者：佚名 2010-01-07 10:46:27

我們今天就通過一段基于服務器中的代碼實現來為大家詳細講解有關VB.NET Socket編程的相關操作方法，希望能對又需要的朋友有所幫助。

VB.NET 應用范圍非常廣泛。我們可以在VB.NET環境中進行一些特定語言的編寫。下面就來看一下VB.NET Socket編程的相關方法。一直以來很想學習Socket編程方面的應用，比如怎樣通過Socket編程實現單片機與PC的TCP連接通信。在單片機嵌入網卡芯片與PC進行連接通信，實現PC的web方式對單片機所控制的設備的狀態管理，例如智能家居方面的應用。#t#

下面通過例子來學習VB.NET Socket編程類的應用，下面的程序是服務器中的代碼實現:

Visual Basic ---tcpserver

Imports System
Imports System.Net
Imports System.Net.Sockets
Imports System.Text
Imports System.Threading
Imports Microsoft.VisualBasic
' State object for reading client
data asynchronously
Public Class StateObject
' Client socket.
Public workSocket As Socket = Nothing
' Size of receive buffer.
Public Const BufferSize As Integer = 1024
' Receive buffer.
Public buffer(BufferSize) As Byte
' Received data string.
Public sb As New StringBuilder
End Class 'StateObject
Public Class AsynchronousSocket
Listener
' Thread signal.
Public Shared allDone As New Manual
ResetEvent(False)
' This server waits for a connection
and then uses asychronous operations to
' accept the connection, get data from
the connected client,
' echo that data back to the
connected client.
' It then disconnects from the
client and waits for another client.
Public Shared Sub Main()
' Data buffer for incoming data.
Dim bytes() As Byte = New [Byte](1023) {}
' Establish the local endpoint for the socket.
Dim ipHostInfo As IPHostEntry =
Dns.Resolve(Dns.GetHostName())
Dim ipAddress As IPAddress =
ipHostInfo.AddressList(0)
Dim localEndPoint As New IPEndPoint
(ipAddress, 11000)
' Create a TCP/IP socket.
Dim listener As New Socket(AddressFamily.
InterNetwork, SocketType.Stream, ProtocolType.Tcp)
' Bind the socket to the local endpoint
and listen for incoming connections.
listener.Bind(localEndPoint)
listener.Listen(100)
While True
' Set the event to nonsignaled state.
allDone.Reset()
' Start an asynchronous socket to listen
for connections.
Console.WriteLine("Waiting for a connection...")
listener.BeginAccept(New AsyncCallback
(AddressOf AcceptCallback), listener)
' Wait until a connection is made and
processed before continuing.
allDone.WaitOne()
End While
End Sub 'Main
Public Shared Sub AcceptCallback(ByVal ar
As IAsyncResult)
' Get the socket that handles the client request.
Dim listener As Socket = CType(ar.AsyncState, Socket)
' End the operation.
Dim handler As Socket = listener.EndAccept(ar)
' Create the state object for the async receive.
Dim state As New StateObject
state.workSocket = handler
handler.BeginReceive(state.buffer, 0, StateObject.
BufferSize, 0, New AsyncCallback(AddressOf
ReadCallback), state)
End Sub 'AcceptCallback
Public Shared Sub ReadCallback(ByVal ar As
IAsyncResult)
Dim content As StringString = String.Empty
' Retrieve the state object and the handler socket
' from the asynchronous state object.
Dim state As StateObject = CType(ar.AsyncState,
StateObject)
Dim handler As Socket = state.workSocket
' Read data from the client socket.
Dim bytesRead As Integer = handler.EndReceive(ar)
If bytesRead > 0 Then
' There might be more data, so store the data
received so far.
state.sb.Append(Encoding.ASCII.GetString
(state.buffer, 0, bytesRead))
' Check for end-of-file tag. If it is not there, read
' more data.
content = state.sb.ToString()
If content.IndexOf("<EOF>") > -1 Then
' All the data has been read from the
' client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. "
+ vbLf + " Data : {1}", content.Length, content)
' Echo the data back to the client.
Send(handler, content)
Else
' Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.
BufferSize, 0, New AsyncCallback(AddressOf
ReadCallback), state)
End If
End If
End Sub 'ReadCallback
Private Shared Sub Send(ByVal handler As Socket,
ByVal data As String)
' Convert the string data to byte data using
ASCII encoding.
Dim byteData As Byte() = Encoding.ASCII.GetBytes(data)
' Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
New AsyncCallback(AddressOf SendCallback), handler)
End Sub 'Send
Private Shared Sub SendCallback(ByVal ar As IAsyncResult)
' Retrieve the socket from the state object.
Dim handler As Socket = CType(ar.AsyncState, Socket)
' Complete sending the data to the remote device.
Dim bytesSent As Integer = handler.EndSend(ar)
Console.WriteLine("Sent {0} bytes to client.", bytesSent)
handler.Shutdown(SocketShutdown.Both)
handler.Close()
' Signal the main thread to continue.
allDone.Set()
End Sub 'SendCallback
End Class 'AsynchronousSocketListener

VB.NET Socket編程的具體用法就為大家介紹到這里。

責任編輯：曹凱來源：博客園

VB.NET Socket編程