VB解释代码

答案：Option Explicit '变量必须先声明后使用
 Private Enum MyState '定义枚举类型MyState
    stClose = 0
    stConnected = 1
  
stDataRequest = 2
 End Enum
 Private WskState As MyState '定义WskState 为枚举类型MyState
  
Private Sub Form_Load() '窗体加载
  
Me.Show '显示窗体
  
Winsock1.Connect "127.0.0.1", "7878" '连接127.0.0.1(本机)的7878端口
  
WskState = stClose 'MyState设为stClose(0)-未连接
 End Sub
  
Private Sub Winsock1_Connect() '建立连接时
  
Print "链接成功"
  
WskState = stConnected 'MyState设为stClose(1)-已连接
 End Sub
  
Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long) '收到数据
  
Dim s As String '存储数据
  
Dim r '字符串数组,用以分割s
  
Dim d() As Byte
  
Static Flen As Long '长度.注:Static:静态变量,其不随Sub结束而释放
  
Static TransLen As Long
  
Dim fname As String '名称
  
Select Case WskState '判断状态
  
    Case stConnected '如果已连接
  
  
   Winsock1.GetData s '获取数据至s
  
  
   r = Split(s, Chr(0)) '以Chr(0)标记分割s至字符串数组r
  
  
  
  
  
    If r(0) = "FILE" And UBound(r) = 3 Then '如果r(0)为"FILE"且s中有4个Chr(0)--即符合预定义格式
  
  
  
  Flen = Val(r(2)) '长度=r(2)的值
  
  
  
  fname = r(1) '名称=r(1)
  
  
  
  While InStr(fname, "\\") > 0 '寻找"\\"符号
  
  
  
  
 fname = Mid(fname, InStr(fname, "\\") + 1) 'fname<--"\\"右边的内容
  
  
  
  Wend
  
  
  
  CommonDialog1.FileName = fname '通用对话框的文件名显示为fname
  
  
  
  
  
  
  
  On Error GoTo Ers '设置错误陷阱,错误执行ERS
  
  
  
  CommonDialog1.CancelError = True '忽略错误
  
  
  
  CommonDialog1.ShowSave '显示"保存文件" 窗口
  
  
  
  
  
  
  
  On Error GoTo 0 '取消上面设置的错误陷阱
  
  
  
  
  
  
  
  Open CommonDialog1.FileName For Output As #1 '创建文件
  
  
  
  Close #1 '本行及上行代码多余,可删.
  
  
  
  Open CommonDialog1.FileName For Binary As #1 '以二进制方式打开文件
  
  
  
  Winsock1.SendData "FILEOK" '发送数据"FILEOK"
  
  
  
  WskState = stDataRequest '设置连接标记
  
  
  
  TransLen = 0 '长度为0
  
  
   End If
  
    Case stDataRequest '如果标记为stDataRequest(可以译作"请求数据"吗???)
  
  
   Winsock1.GetData d(), vbArray + vbByte, bytesTotal '获取数据
  
  
   TransLen = TransLen + bytesTotal '设置长度
  
  
  
  If TransLen >= Flen Then '如本长度<文件长度
  
  
  
  Dim i As Long
  
  
  
  For i = 0 To Flen Mod bytesTotal '循环写入文件
  
  
  
  
 Put #1, , d(i) '写入文件
  
  
  
  Next i
  
  
  
  
  
  
  
  WskState = stConnected '设置连接标记
  
  
  
  Winsock1.SendData "DATAOK" '发送数据"DATAOK"
  
  
  
  Close #1 '关闭文件
  
  
   Else '否则
  
  
  
  Put #1, , d '将d()写入文件
  
  
  
  Winsock1.SendData "PACKETOK" '发送数据"PACKETOK"
  
  
   End If
  
    Case Else '如果标记为stClose
  
  
   Winsock1.GetData s '获取数据至s
  
  
   Print "Unknown reuqest :" & s '未知请求:s
  
End Select
  
Exit Sub
 Ers: '按下取消
  
Winsock1.SendData "CANCEL" '发送识别码
  
Print "拒绝传输"
 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) '连接出错
  
Winsock1.Close '关闭连接
  
Call Form_Load '重建连接
 End Sub

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