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程式設計工藝大師

TCP $ UDP

張運晟

TCP 和 UDP 差異

                   
                    優點                                        缺點

TCP         傳送可靠，                             速度較慢  
            　程式可省略可靠機制

UDP    　傳輸量大且迅速                     資料傳輸不可靠，沒有可靠機制
                資料可能會遺失

圖片來源

Example


TCP Server

Option Explicit

Private Sub cmdSend_Click()

  Winsock1.SendData txtSend.Text

End Sub

Private Sub Form_Load()

  Winsock1.LocalPort = 7777

  Winsock1.Listen  '監聽

End Sub

Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)

  Dim strData As String

  Winsock1.GetData strData, vbString

  txtReceived.Text = strData

  If strData = "close" Then

    Winsock1.Close

    cmdSend.Enabled = False

    Winsock1.Listen

  End If

End Sub

Private Sub Winsock1_ConnectionRequest(ByVal requestID As Long)

MsgBox "有人敲門!"

  Winsock1.Close

  Winsock1.Accept requestID  '改成接受

  cmdSend.Enabled = True

End Sub

TCP Cleint

Private Sub cmdConnect_Click()

  Winsock1.LocalPort = 6666   '以便自動產生Local Port

  Winsock1.Connect "192.168.15.53"  '設定改成您 Server 電腦的IP 號碼

End Sub

Private Sub cmdExit_Click()

  Winsock1.SendData "close"

  DoEvents

  Winsock1.Close

  Winsock1.LocalPort = 0

End Sub

Private Sub cmdSend_Click()

  Winsock1.SendData txtOutput.Text

  DoEvents

End Sub

Private Sub Form_Load()

  Winsock1.RemotePort = 7777  '設定與Server端做Listen的Port相同

End Sub

Private Sub Form_Unload(Cancel As Integer)

If Winsock1.State <> sckClosed Then

   cmdExit_Click

End If

End Sub

Private Sub Winsock1_Connect()

If Winsock1.State = sckConnected Then

   lstInput.AddItem "Connected! LocalPort =" & Winsock1.LocalPort _

                    & " RemptePort = " & Winsock1.RemotePort

End If

End Sub

Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)

  Dim mydata As String

  Winsock1.GetData mydata, vbString

  lstInput.AddItem mydata

End Sub

Private Sub Winsock1_Error(ByVal Number As Integer, Description As String, ByVal Scode As Long, ByVal Source As String, ByVal HelpFile As String, ByVal HelpContext As Long, CancelDisplay As Boolean)

  lstInput.AddItem Description

End Sub

只需要在紅色地方 更改

Local Port  不能跟目的的Port一樣