VB局域网文件传输带防止丢包.docx

不知道你的winsock?是udp还是tcpip协议这里给你一个我写的实例?我是用的udp?这个发送了一段数据不一定接收就正确?所以我做了校验???以下是发送文件的Option?ExplicitDim?GetFileNum?As?Integer,?LenFile?As?Long,?SendByte()?As?Byte?发送的包Private?Sub?Command1_Click()On?Error?Resume?NextCommand1.Enabled?=?FalseGetFileNum?=?FreeFile?取得未使用的文件号LenFile?=?FileLen(Text1.Text)?获得需传送的文件的长度If?Text2.Text?=??Or?Right(Left(Text2.Text,?2),?1)??:?Then?Text2.Text?=?Text1.TextWinsock0.SendData?#SEND?STA#??LenFile??//??Text2.TextWt?0.5Open?Text1.Text?For?Binary?As?#GetFileNum?打开需传送的文件Call?TCPSendFile(Winsock0,?GetFileNum,?SplitFile)?传送文件Me.Caption?=?NowTi.Enabled?=?TrueEnd?SubPrivate?Sub?Command2_Click()Unload?MeEnd?SubPrivate?Sub?Form_Load()Dim?A?As?StringOn?Error?Resume?NextCommand2.Top?=?-2000Winsock0.RemoteHost?=?IPX?服务器ipWinsock0.RemotePort?=?FilePortEnd?SubPrivate?Function?SplitFile()?As?Long?拆包为了清晰,下面分别用两个子过程来完成计算这次还可以传多少个字节的数据和传送数据On?Error?Resume?NextDim?GetCount?As?LongIf?LenFile?=?4000?Then?计算出这次可发送的字节数? ? GetCount?=?4000? ? LenFile?=?LenFile?-?GetCountElse? ? GetCount?=?LenFile? ? LenFile?=?LenFile?-?GetCountEnd?IfSplitFile?=?GetCountEnd?FunctionPrivate?Sub?TCPSendFile(objWinSock?As?Winsock,?FileNumber?As?Integer,?SendLen?As?Long)On?Error?Resume?NextDim?FileByte()?As?Byte,?I?As?Long,?j?As?Long,?Temp?As?String?*?4ReDim?SendByte(0)ReDim?FileByte(SendLen?-?1)Temp?=?SendLen?+?7SendByte?=?Temp?把长度负值给包头Get?#FileNumber,?,?FileByte?读取文件ReDim?Preserve?SendByte(SendLen?+?7)?把包头+到文件头For?I?=?0?To?UBound(FileByte)? ? SendByte(I?+?7)?=?FileByte(I)? ? DoEventsNextWinsock0.SendData?SendByteEnd?SubPrivate?Sub?Form_Unload(Cancel?As?Integer)On?Error?Resume?NextWinsock0.CloseErr.ClearEnd?SubPrivate?Sub?TEnd_Timer()On?Error?Resume?NextWinsock0.SendData?#END#Err.ClearEnd?SubPrivate?Sub?Ti_Timer()On?Error?Resume?NextWinsock0.SendData?#ERR#End?SubPrivate?Sub?Winsock0_DataArrival(ByVal?bytesTotal?As?Long)On?Error?Resume?NextDim?S?As?StringWinsock0.GetData?SSelect?Case?SCase?ok?成功继续发送? ? If?LenFile?=?0?Then?发送完成? ? ? ? If?S??#SEND?END#?Then?Winsock0.SendData?#SEND?END#? ?