VB.NET FTP登录类

Imports SystemImports System.NetImports System.IOImports System.TextImports System.Net.SocketsPublic Class Class1    Public Const BLOCK_SIZE = 512    Private Obj_ClientSocket As Socket    Private Str_Domain As String = "XXX"          'ftp服务器地址    Private Str_User As String = "XXX"                      'ftp登陆帐号    Private Str_Password As String = "XXX"    'ftp登陆密码    Private Int_RemotePort As Integer = 21              'ftp服务器端口    Private Int_Reply, Int_Bytes As Int32    Private Str_Message, Str_Reply As String    Private Byte_Buffer(BLOCK_SIZE) As Byte    Private ASCII As Encoding = Encoding.ASCII    Public Function Logined() As Boolean        Obj_ClientSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)        Dim x_lob As New IPEndPoint(Dns.GetHostEntry(Str_Domain).AddressList(0), Int_RemotePort)        Try            Obj_ClientSocket.Connect(x_lob)        Catch ex As Exception            MsgBox("无法登陆远程Ftp服务器")        End Try        Str_Message = ""        Str_Reply = ServerReply()        Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))        If (Int_Reply <> 220) Then            MsgBox(Str_Reply.Substring(4))        End If        SendCommand("USER " & Str_User)        Str_Reply = ServerReply(True)        Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))        If (Not (Int_Reply = 331 Or Int_Reply = 230)) Then            MsgBox(Str_Reply.Substring(4))            Return False        End If        If (Int_Reply <> 230) Then            SendCommand("PASS " & Str_Password)            Str_Reply = ServerReply(True)            Int_Reply = Int32.Parse(Str_Reply.Substring(0, 3))            If (Not (Int_Reply = 230 Or Int_Reply = 202)) Then                MsgBox(Str_Reply.Substring(4))                Return False            End If        End If        Return True    End Function    Private Function ServerReply(Optional ByVal Bool_Clear As Boolean = False) As String        Dim Sep As Char = ControlChars.Lf        Dim Arr_Msg() As String        If (Bool_Clear) Then            Str_Message = ""        End If        Do While (True)            Array.Clear(Byte_Buffer, 0, BLOCK_SIZE)            Int_Bytes = Obj_ClientSocket.Receive(Byte_Buffer, Byte_Buffer.Length, 0)            Str_Message += ASCII.GetString(Byte_Buffer, 0, Int_Bytes)            If (Int_Bytes < Byte_Buffer.Length) Then                Exit Do            End If        Loop        Arr_Msg = Str_Message.Split(Sep)        If (Str_Message.Length > 2) Then            Str_Message = Arr_Msg(Arr_Msg.Length - 2)        Else            Str_Message = Arr_Msg(0)        End If        If (Not (Str_Message.Substring(3, 1).Equals(" "))) Then            Return ServerReply(True)        End If        Return Str_Message    End Function    Private Sub SendCommand(ByVal Str_Command As String)        Str_Command = Str_Command & ControlChars.CrLf        Dim cmdbytes As Byte() = ASCII.GetBytes(Str_Command)        Obj_ClientSocket.Send(cmdbytes, cmdbytes.Length, 0)    End SubEnd Class

网上找到的一个VB.NET的FTP类文件，能够不错的兼容使用，但是还是存在一些问题，现在整合在AspCms内容管理器上，在寒假里希望能进行一下改进，加入上传下载的功能。