在Visual Basic（VB）中实现局域网联机编程来下象棋，可以通过使用Winsock控件来创建一个服务器端程序，用于接收和发送棋盘信息，以及一个或多个客户端程序用于连接服务器并进行游戏。以下是一个基本的实现步骤和示例代码：
创建服务器端程序
打开Visual Basic，创建一个新的Windows应用程序项目。
在项目中添加一个Winsock控件。
编写服务器端代码，包括创建Winsock对象、绑定IP地址和端口号、监听连接、接受客户端连接、发送和接收数据等。
创建客户端程序
同样在Visual Basic中创建一个新的Windows应用程序项目。
在项目中添加一个Winsock控件。
编写客户端代码，包括创建Winsock对象、连接到服务器、发送和接收数据等。
实现联机对战逻辑
在服务器端，当客户端连接成功后，将当前棋盘的布局发送给客户端。
在客户端，接收服务器发送的棋盘布局并显示在界面上。
实现棋子的移动逻辑，并在移动后更新棋盘布局并发送回服务器。
处理游戏结束和错误情况
当一方将死对方时，游戏结束，可以在服务器端或客户端检测到游戏结束的条件并通知对方。
处理网络错误和异常情况，如连接中断、数据传输错误等。
服务器端代码示例：
```vb
Imports System.Net.Sockets
Imports System.Text
Public Class Server
Private Const PORT As Integer = 12345
Private Const MAX_CLIENTS As Integer = 10
Private clients As New List(Of TcpClient)()
Private chessBoard As String() = New String(7, 7) {} ' 8x8 chess board
Private Sub StartServer()
Dim server As New TcpListener(IPAddress.Any, PORT)
server.Start()
Console.WriteLine("Server started, waiting for connections...")
While True
Dim client As TcpClient = server.AcceptTcpClient()
If clients.Count < MAX_CLIENTS Then
clients.Add(client)
Console.WriteLine("Client connected.")
HandleClient(client)
Else
Console.WriteLine("Server is full.")
client.Close()
End If
End While
End Sub
Private Sub HandleClient(client As TcpClient)
Dim stream As NetworkStream = client.GetStream()
Dim reader As New StreamReader(stream)
Dim writer As New StreamWriter(stream)
' Send initial chess board to client
For i As Integer = 0 To 7
For j As Integer = 0 To 7
writer.WriteLine(chessBoard(i, j))
Next
Next
While True
Dim message As String = reader.ReadLine()
If message = "MOVE" Then
' Handle move request from client
' Update chess board and send new board to client
Else
Console.WriteLine("Received unknown message: " & message)
End If
End While
End Sub
End Class
```
客户端代码示例：
```vb
Imports System.Net.Sockets
Imports System.Text
Public Class Client
Private Const SERVER_IP As String = "127.0.0.1"
Private Const SERVER_PORT As Integer = 12345
Private Sub StartClient()
Dim client As New TcpClient(SERVER_IP, SERVER_PORT)
Dim stream As NetworkStream = client.GetStream()
Dim reader As New StreamReader(stream)
Dim writer As New StreamWriter(stream)
' Receive initial chess board from server
For i As Integer = 0 To 7
chessBoard(i) = reader.ReadLine()
Next
' Handle incoming messages from server
While True
Dim message As String = reader.ReadLine()
Console.WriteLine("Received message: " & message)
' Process move and send move request to server
End While
End Sub
End Class
```
请注意，这只是一个非常基础的示例，实际应用中需要添加更多的错误处理、游戏逻辑和用户界面功能。此外，为了确保游戏的公平性和安全性，还需要考虑加密通信、身份验证和防止作弊等安全措施