' Displays sending with a connected socket
' using the overload that takes a buffer, offset, message size, and socket flags.
Public Shared Function SendReceiveTest4(ByVal server As Socket) As Integer 
    Dim msg As Byte() = Encoding.UTF8.GetBytes("This is a test")
    Dim bytes(255) As Byte
    Try
        ' Blocks until send returns.
        Dim byteCount As Integer = server.Send(msg, 0, msg.Length, SocketFlags.None)
        Console.WriteLine("Sent {0} bytes.", byteCount)
        
        ' Get reply from the server.
        byteCount = server.Receive(bytes, 0, server.Available, SocketFlags.None)
        
        If byteCount > 0 Then
            Console.WriteLine(Encoding.UTF8.GetString(bytes))
        End If
    Catch e As SocketException
        Console.WriteLine("{0} Error code: {1}.", e.Message, e.ErrorCode)
        Return e.ErrorCode
    End Try
    Return 0

End Function 'SendReceiveTest4

' 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

' Displays sending with a connected socket
' using the overload that takes a buffer and socket flags.
Public Shared Function SendReceiveTest2(ByVal server As Socket) As Integer 
    Dim msg As Byte() = Encoding.UTF8.GetBytes("This is a test")
    Dim bytes(255) As Byte
    Try
        ' Blocks until send returns.
        Dim byteCount As Integer = server.Send(msg, SocketFlags.None)
        Console.WriteLine("Sent {0} bytes.", byteCount)
        
        ' Get reply from the server.
        byteCount = server.Receive(bytes, SocketFlags.None)
        If byteCount > 0 Then
            Console.WriteLine(Encoding.UTF8.GetString(bytes))
        End If
    Catch e As SocketException
        Console.WriteLine("{0} Error code: {1}.", e.Message, e.ErrorCode)
        Return e.ErrorCode
    End Try
    Return 0

End Function 'SendReceiveTest2

' Displays sending with a connected socket
' using the overload that takes a buffer.
Public Shared Function SendReceiveTest1(ByVal server As Socket) As Integer 
    Dim msg As Byte() = Encoding.UTF8.GetBytes("This is a test")
    Dim bytes(255) As Byte
    Try
        ' Blocks until send returns.
        Dim i As Integer = server.Send(msg)
        Console.WriteLine("Sent {0} bytes.", i)
        
        ' Get reply from the server.
        i = server.Receive(bytes)
        Console.WriteLine(Encoding.UTF8.GetString(bytes))
    Catch e As SocketException
        Console.WriteLine("{0} Error code: {1}.", e.Message, e.ErrorCode)
        Return e.ErrorCode
    End Try
    Return 0

End Function 'SendReceiveTest1

' 导入命名空间
Imports System
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports System.Text

Public Class DateTimeClient
  Public Shared Sub Main()
    Dim args As String() = Environment.GetCommandLineArgs()

    Dim serverHost As String = "127.0.0.1"

    Dim hostadd As IPAddress = Dns.Resolve(serverHost).AddressList(0)
    Dim EPhost As New IPEndPoint(hostadd, 13)
    Dim clientSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)


    Try
      clientSocket.Connect(EPhost)
    Catch ex As Exception
      Console.WriteLine(ex.ToString())
    End Try

    Try
      Dim recvbytes(1024) As Byte
      Dim i As Integer = clientSocket.Receive(recvbytes, 0, clientSocket.Available, SocketFlags.None)

      Dim datetime As String = Encoding.ASCII.GetString(recvbytes, 0, i)

      Console.WriteLine("Receive {0} bytes.", i)
      Console.WriteLine("Current server date/Time: {0}", datetime)

      clientSocket.Shutdown(SocketShutdown.Both)
      clientSocket.Close()
    Catch ec As Exception
      Console.WriteLine(ec.StackTrace.ToString())
      Exit Sub
    End Try
  End Sub
End Class