VB TCP 對外通訊與接收

.Net FrameWork 在 TCP/IP 通訊上支援的十分好. 幾乎只要 GOOGLE 之後就可以找出答案. 真正的問題在於, 接收和發送, 如果要顯示在 FORM 上, 仍然必須用 "委派" 的方式. 天下文章一大抄, 只要抄對了就好. 如果你考慮使用多工, 要小心通訊埠多次開啟的錯誤. 而主要是採用 TcpListener 為主. 重點要注意的是, 對外通訊必須使用 "192.168.XX.XX" 或 "10.X.X.X" 的 IP, 而不能使用 "127.0.0.1". 經實驗, 127.0.0.1 在 VB 對 VB 連線是沒問題的, 但是ANDROID 對 PC 連, 就會連不到. 另外, 收到的字元長度, 緩衝區定義為 1024, 長度就是 1024, 即使只傳了1個字, 其長度依然是 1024, 其它的字元都是 CHR(0). 所以你在判斷ANDROID傳回什麼答案時, 必須將CHR(0) 去掉才能進行判斷. 中文部份, 使用 UNICODE ENCODING 是可以接收到. 但是顯示時會有亂碼, (理論上 ANDROID 應該也是 UNICODE). 所以在轉換時, 請特別小心. 以下程式為支援 andriod 與 PC 通訊的 PC 端程式. Imports System Imports System.ComponentModel Imports System.Threading Imports System.Windows.Forms Imports System.Net.Sockets Imports System.Net Imports System.Text Private Class CSState Public myTcpListener As TcpListener Public ClientSocket As Socket Public mystring As String End Class Private myDatatable As New DataTable Private myTcpListener As TcpListener Delegate Sub SetMsgCallBack(ByVal state As Object) Private Sub DisplayMsg1(ByVal state As Object) Dim myObj As New CSState myObj = CType(state, CSState) If Me.DataGridView1.InvokeRequired Then Dim d As New SetMsgCallBack(AddressOf DisplayMsg1) Me.Invoke(d, New Object() {myObj}) Else Dim xRow As DataRow = myDatatable.NewRow() xRow.Item(0) = CType(myObj.ClientSocket.RemoteEndPoint, IPEndPoint).Address.ToString() xRow.Item(1) = CType(myObj.ClientSocket.RemoteEndPoint, IPEndPoint).Port.ToString() xRow.Item(2) = myObj.mystring myDatatable.Rows.Add(xRow) End If End Sub Private Sub Form1_Load_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Activated myDatatable.Columns.Add("IP") myDatatable.Columns.Add("Port") myDatatable.Columns.Add("Data") DataGridView1.DataSource = myDatatable DataGridView1.Columns(2).Width = 150 Dim iPort As Integer iPort = "1024" Dim ListenThread As New Thread(AddressOf StartListen) ListenThread.IsBackground = True ListenThread.Start(iPort) End Sub Private Sub StartListen(ByVal state As Object) Dim iPort As Integer iPort = CType(state, Integer) myTcpListener = New TcpListener(IPAddress.Any, iPort) Try Dim ClientSocket As Socket myTcpListener.Start() Dim iCount As Integer = 0 Do ClientSocket = myTcpListener.AcceptSocket() If ClientSocket.Connected = True Then Dim myObj As New CSState myObj.myTcpListener = myTcpListener myObj.ClientSocket = ClientSocket myObj.mystring = Now.ToString("yyyy/MM/dd HH:mm:ss") & "已連線" DisplayMsg1(myObj) Dim ReceiveThread As New Thread(AddressOf ReceiveData) ReceiveThread.IsBackground = True ReceiveThread.Start(myObj) iCount += 1 End If Loop Catch ex As Exception MessageBox.Show(ex.ToString()) End Try End Sub Private Sub ReceiveData(ByVal state As Object) Dim myObj As New CSState myObj.ClientSocket = CType(state, CSState).ClientSocket myObj.myTcpListener = CType(state, CSState).myTcpListener myObj.mystring = "" Dim myNetworkStream As New NetworkStream(myObj.ClientSocket) Dim InBytesCount As Integer = 0 Dim myReceiveBytes(1023) As Byte Dim i As Integer = 0 While True Try InBytesCount = myNetworkStream.Read(myReceiveBytes, 0, myReceiveBytes.Length) System.Threading.Thread.Sleep(100) If InBytesCount = 0 Then Exit While End If myObj.mystring = Replace(Encoding.GetEncoding(950).GetString(myReceiveBytes).TrimEnd().TrimStart(), Chr(0), "") DisplayMsg1(myObj) 'If (myObj.mystring.Equals("xxx")) Then Dim myWriteBuffer As Byte() = Encoding.GetEncoding(950).GetBytes("Received: " + myObj.mystring) myNetworkStream.Write(myWriteBuffer, 0, myWriteBuffer.Length) System.Threading.Thread.Sleep(100) 'End If Catch ex As Exception MessageBox.Show(ex.ToString) Exit Sub End Try End While End Sub