NEU

ServerListender/frmMain2.vb

@@ -0,0 +1,128 @@
+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 AsynchronousSocketListener
+    ' Thread signal.
+    Public Shared allDone As New ManualResetEvent(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 IPEndPoint = New IPEndPoint(IPAddress.Any, 4000)
+
+        ' 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)
+        MsgBox("start")
+        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)
+        MsgBox("yey1")
+        ' 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)
+        MsgBox("yey")
+        Dim content As String = 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