fmvbftpjr.frm

vb网络通信协议,参考例程

VERSION 5.00
Object = "{6B7E6392-850A-101B-AFC0-4210102A8DA7}#1.3#0"; "COMCTL32.OCX"
Begin VB.Form frmFTPst 
   Caption         =   "FTP客户端程序"
   ClientHeight    =   1650
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5265
   LinkTopic       =   "Form1"
   ScaleHeight     =   1650
   ScaleWidth      =   5265
   StartUpPosition =   3  '窗口缺省
   Begin VB.Frame Frame2 
      Caption         =   "代理服务器"
      Height          =   1350
      Left            =   2520
      TabIndex        =   3
      Top             =   135
      Width           =   2685
      Begin VB.TextBox txtProxyPort 
         Appearance      =   0  'Flat
         Enabled         =   0   'False
         Height          =   300
         Left            =   675
         TabIndex        =   7
         Top             =   735
         Width           =   840
      End
      Begin VB.TextBox txtProxy 
         Appearance      =   0  'Flat
         Enabled         =   0   'False
         Height          =   285
         Left            =   660
         TabIndex        =   4
         Top             =   240
         Width           =   1905
      End
      Begin VB.Label Label5 
         Caption         =   "端口："
         Height          =   300
         Left            =   120
         TabIndex        =   6
         Top             =   780
         Width           =   585
      End
      Begin VB.Label Label1 
         Caption         =   "地址："
         Height          =   285
         Left            =   120
         TabIndex        =   5
         Top             =   300
         Width           =   570
      End
   End
   Begin VB.Frame Frame1 
      Caption         =   "打开及关闭会话"
      Height          =   1365
      Left            =   180
      TabIndex        =   0
      Top             =   165
      Width           =   2175
      Begin VB.CommandButton cmdInternetOpen 
         Caption         =   "打开Internet会话"
         Height          =   330
         Left            =   315
         TabIndex        =   2
         Top             =   330
         Width           =   1665
      End
      Begin VB.CommandButton cmdClosehOpen 
         Caption         =   "关闭Internet会话"
         Height          =   330
         Left            =   315
         TabIndex        =   1
         Top             =   780
         Width           =   1665
      End
   End
   Begin ComctlLib.ImageList ImageList1 
      Left            =   2520
      Top             =   6300
      _ExtentX        =   1005
      _ExtentY        =   1005
      BackColor       =   -2147483643
      MaskColor       =   12632256
      _Version        =   327682
   End
End
Attribute VB_Name = "frmFTPst"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit
Private Sub Form_Load()
    bActiveSession = False
    hOpen = 0
    hConnection = 0
    cmdClosehOpen.Enabled = False
    End Sub

Private Sub Form_Unload(Cancel As Integer)
    cmdClosehOpen_Click
End Sub

Private Sub cmdInternetOpen_Click()
'在建立一定类型的Internet连接前，必须首先建立Internet对话，如果成功建立
'Internet对话，则返回一个句柄作为建立相应类型的连接（在这里是FTP连接）
'InternetConnect（）的参数
    If Len(txtProxy.Text) <> 0 Then
        hOpen = InternetOpen(scUserAgent, INTERNET_OPEN_TYPE_PROXY, txtProxy.Text, vbNullString, 0)
    Else
        hOpen = InternetOpen(scUserAgent, INTERNET_OPEN_TYPE_DIRECT, vbNullString, vbNullString, 0)
    End If
    '打开internet连接的线程后，根据打开的结果设置各个按扭的状态
    If hOpen = 0 Then
    MsgBox "不能打开Internet连接", vbCritical
    cmdInternetOpen.Enabled = False
    cmdClosehOpen.Enabled = True
    Else
    frmFTPst.cmdClosehOpen.Enabled = True
    frmFTPst.cmdInternetOpen.Enabled = False
    '如果打开成功，以模式对话框显示主窗体frmFTP2
    frmFTP2.Show vbModal
    End If
End Sub

Private Sub cmdClosehOpen_Click()
'关闭连接，将所有的Internet连接的句柄关闭
'清除所有的对象集合和窗体中的文本框的内容
    If hConnection <> 0 Then
    InternetCloseHandle (hConnection)
    End If
    If hOpen <> 0 Then
    InternetCloseHandle (hOpen)
    End If
    hConnection = 0
    hOpen = 0
    bActiveSession = False
    cmdInternetOpen.Enabled = True
End Sub