程序中如何启动默认的拨号连接随着因特网的迅猛发展,现在编程常需要在程序中直接联网来处理一些事项,如在线注册和在线帮助,这就要求我们要在程序中建立某些连接。很多软件在不知用户是否联网的情况下不管三七二十一就启动浏览器查找网址,费了九牛二虎之力只能查出一错误页来(当然不可能有什么好的结果)。如果我们在程序编写时能自动判断用户是否已经联网,如已经联网则打开联接,如没有则启动默认的拨号连接,这样是不是让人觉得你的软件更胜人一处呢?判断是否已联网很多地方都有介绍,这里我们只介绍如何启动默认的拨号连接。
---- 在介绍之前让我们首先看看如何打开拨号网络。由于拨号网络不是一个可执行文件,所以不能用 “Shell 可执行文件”的方式来打开。要启动拨号网络,需借助 Explorer ,方法如下: Shell "Explorer ::{20D04FE0-3AEA-1069-A2D8-08002B30309D}\" & "::{992CFFA0-F557-101A-88EC-00DD010CCC48}", vbNormalFocus
---- 但若是要启动拨号网络中的某一个连接,则需借助rundll.exe 及 rnaui.dll来启动,方法如下(假定连接名称为163): Shell "rundll rnaui.dll,RnaDial 163", vbNormalFocus
---- 说明:在以上叙述中,“,RnaDial 163”这部分不要插入额外的空格,大小写也不要任意更改。 ---- 上面仅仅假定了连接名称,但实际编程中我们是不知道其名称的,如何取得默认的连接名称并启动它呢?这里我们可利用注册表来达到目的。完整程序如下: ---- 在窗体上放置一个命令按钮(名称为 cmdCallConnect),下面为代码部份: Option Explicit
'有关注册的API声明
Private Declare Function RegOpenKeyEx Lib "advapi32" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As LongPrivate Declare Function RegQueryValueEx Lib "advapi32" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, ByRef lpType As Long, ByVal szData As String, ByRef lpcbData As Long) As LongPrivate Declare Function RegCloseKey Lib "advapi32" (ByVal hKey As Long) As Long
'常数
Const HKEY_CURRENT_USER = &H80000001
Const ERROR_SUCCESS = 0&
Private Sub cmdCallConnect_Click()
'启动默认拨号连接
Shell "rundll rnaui.dll,RnaDial " + GetConnect, vbNormalFocus
End Sub
Public Function GetConnect() As String
Dim hKey As Long
Dim SubKey As String
hKey = HKEY_CURRENT_USER '主键
SubKey = "RemoteAccess" '子键
'取得默认连接名
GetConnect = GetRegValue(hKey, SubKey, "Default")
End FunctionPublic Function GetRegValue(hKey As Long, lpszSubKey As String, szKey As String) As Variant
On Error GoTo ErrorRoutineErr:
Dim phkResult As Long
Dim lResult As Long
Dim szBuffer As String
Dim lBuffSize As Long'创建缓冲区
szBuffer = Space(255)
lBuffSize = Len(szBuffer)'打开注册键
RegOpenKeyEx hKey, lpszSubKey, 0, 1, phkResult'查询结果
lResult = RegQueryValueEx(phkResult,szKey, 0, 0, szBuffer,lBuffSize)'关闭注册键
RegCloseKey phkResult'返回结果
If lResult = ERROR_SUCCESS Then
GetRegValue = Left(szBuffer, lBuffSize - 1)
Else
GetRegValue = ""
End If
Exit FunctionErrorRoutineErr:
GetRegValue = ""
End Function
以上程序在 WIN98,VB6.0 下调试通过。
---- 在介绍之前让我们首先看看如何打开拨号网络。由于拨号网络不是一个可执行文件,所以不能用 “Shell 可执行文件”的方式来打开。要启动拨号网络,需借助 Explorer ,方法如下: Shell "Explorer ::{20D04FE0-3AEA-1069-A2D8-08002B30309D}\" & "::{992CFFA0-F557-101A-88EC-00DD010CCC48}", vbNormalFocus
---- 但若是要启动拨号网络中的某一个连接,则需借助rundll.exe 及 rnaui.dll来启动,方法如下(假定连接名称为163): Shell "rundll rnaui.dll,RnaDial 163", vbNormalFocus
---- 说明:在以上叙述中,“,RnaDial 163”这部分不要插入额外的空格,大小写也不要任意更改。 ---- 上面仅仅假定了连接名称,但实际编程中我们是不知道其名称的,如何取得默认的连接名称并启动它呢?这里我们可利用注册表来达到目的。完整程序如下: ---- 在窗体上放置一个命令按钮(名称为 cmdCallConnect),下面为代码部份: Option Explicit
'有关注册的API声明
Private Declare Function RegOpenKeyEx Lib "advapi32" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As LongPrivate Declare Function RegQueryValueEx Lib "advapi32" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, ByRef lpType As Long, ByVal szData As String, ByRef lpcbData As Long) As LongPrivate Declare Function RegCloseKey Lib "advapi32" (ByVal hKey As Long) As Long
'常数
Const HKEY_CURRENT_USER = &H80000001
Const ERROR_SUCCESS = 0&
Private Sub cmdCallConnect_Click()
'启动默认拨号连接
Shell "rundll rnaui.dll,RnaDial " + GetConnect, vbNormalFocus
End Sub
Public Function GetConnect() As String
Dim hKey As Long
Dim SubKey As String
hKey = HKEY_CURRENT_USER '主键
SubKey = "RemoteAccess" '子键
'取得默认连接名
GetConnect = GetRegValue(hKey, SubKey, "Default")
End FunctionPublic Function GetRegValue(hKey As Long, lpszSubKey As String, szKey As String) As Variant
On Error GoTo ErrorRoutineErr:
Dim phkResult As Long
Dim lResult As Long
Dim szBuffer As String
Dim lBuffSize As Long'创建缓冲区
szBuffer = Space(255)
lBuffSize = Len(szBuffer)'打开注册键
RegOpenKeyEx hKey, lpszSubKey, 0, 1, phkResult'查询结果
lResult = RegQueryValueEx(phkResult,szKey, 0, 0, szBuffer,lBuffSize)'关闭注册键
RegCloseKey phkResult'返回结果
If lResult = ERROR_SUCCESS Then
GetRegValue = Left(szBuffer, lBuffSize - 1)
Else
GetRegValue = ""
End If
Exit FunctionErrorRoutineErr:
GetRegValue = ""
End Function
以上程序在 WIN98,VB6.0 下调试通过。
http://www.applevb.com/sourcecode/connect_to_net.zip一个比较完成的tapi程序,包括一个包含全部tapi定义的模块和一个tapi类,包括查看以建立的tapi连接、拨号、中断连接以及对线路和拨号进行设置。
http://www.applevb.com/sourcecode/tapi_src.zip
http://www.applevb.com/sourcecode/connect_to_net.zip一个比较完成的tapi程序,包括一个包含全部tapi定义的模块和一个tapi类,包括查看以建立的tapi连接、拨号、中断连接以及对线路和拨号进行设置。
http://www.applevb.com/sourcecode/tapi_src.zip
If IsConnected = TRUE Then
MsgBox (“您已经连通了Internet!”)
End If
If IsConnected = FALSE Then
MsgBox (“您还没有连通 Internet!”)
End If
End Sub
Option Explicit
/*有关的API声明和定义*/
Public Declare Function RasEnumConnections Lib “RasApi32.dll” Alias “RasEnumConnectionsA” (lpRasCon As Any, lpcb As Long, lpcConnections As Long) As Long
Public Declare Function RasGetConnectStatus Lib “RasApi32.dll” Alias “RasGetConnectStatusA” (ByVal hRasCon As Long, lpStatus As Any) As Long
/*常数和变量的设定*/
Public Const RAS95_MaxEntryName = 256
Public Const RAS95_MaxDeviceType = 16
Public Const RAS95_MaxDeviceName = 32
Public Type RASCONN95
dwSize As Long
hRasCon As Long
szEntryName(RAS95_MaxEntryName) As Byte
szDeviceType(RAS95_MaxDeviceType) As Byte
szDeviceName(RAS95_MaxDeviceName) As Byte
End Type
Public Type RASCONNSTATUS95
dwSize As Long
RasConnState As Long
dwError As Long
szDeviceType(RAS95_MaxDeviceType) As Byte
szDeviceName(RAS95_MaxDeviceName) As Byte
End Type
/*函数IsConnected返回连通的状态,如果为True则表示已连通*/
Public Function IsConnected() As Boolean
Dim TRasCon(255) As RASCONN95
Dim lg As Long
Dim lpcon As Long
Dim RetVal As Long
Dim Tstatus As RASCONNSTATUS95
TRasCon(0).dwSize = 412
lg = 256 * TRasCon(0).dwSize
RetVal = RasEnumConnections(TRasCon(0), lg, lpcon)
If RetVal <> 0 Then
MsgBox “错误”
Exit Function
End If
Tstatus.dwSize = 160
RetVal = RasGetConnectStatus(TRasCon(0)
.hRasCon,Tstatus)
If Tstatus.RasConnState = &H2000 Then
IsConnected = TRUE
Else
IsConnected = FALSE
End If
End Function
--------------------------------------------------------------------------------
利用WIN95中的注册表建植,在注册表的HKEY-LOCAL-MACHINE\System\CurrentControlSet\Services\RemoteAcces\下,当计算机连上因特网时,Remote Connection的植为01 00 00 00,反之,为00 00 00 00,通过这一建植可判断是否连网。 1.建立新模块
Public Const ERROR-SUCCESS= 0&
Public Const APINULL= 0&
Public Const HKEY-LOCAL-MACHINE= &H80000002
Public ReturnCode As long
’声明API函数
RegCloseKey()
RegQueryValueEx() ’自定义函数
Public function ActiveConnection() As Boolean Dim hKey As long
Dim lpSubKey As string
Dim lpReserved As long
Dim lpType As long
Dim lpData As long
Dim lpcbData As long ActiveConnection=False
lpSubKey="System\CurrentControlSet\Services\RemoteAccess"
ReturnCode=RegOpenKey(HKEY-LOCAL-MACHINE,lpSubKey,phkResult) If ReturnCode=ERROR-SUCCESS then
hKey=phkResult
lpValueName="Remote Connection"
lpReserved=APINULL
lpType=APINULL
lpData=APINULL
lpcbData=APINULL
ReturnCode=RegQueryValueEx(hKey,lpValueName,lpReserved,lpType,ByVal lpData,lpcbata)
lpcbData=Len(lpData)
ReturnCode=RegQueryValueEx(hKey,lpValueName,lpReserved,lpType,ByVal lpData,lpcbata) If ReturnCode=ERROR-SUCCESS then
If lpData=0 then
ActiveConnection=False
Else
ActiveConnection=True
End If
End If
RegCloseKey(hKey)
End If
End funtion 2.新建窗体
Priate sub Command1_click()
If ActiveConnection=True then
MsgBox "OK!"
Else
MsgBox "ERROR!"
End If
End sub
---- 为了运行下面这个例子,首先需要建立一个窗体,在窗体上放置一个按钮,然后输入以下语句: Option Explicit
Private Declare Function RasHangUp Lib
"RasApi32.DLL" Alias "RasHangUpA"
(ByVal hRasConn As Long) As Long
Private Declare Function RasEnumConnections
Lib "RasApi32.DLL" Alias "RasEnumConnectionsA"
(lprasconn As Any, lpcb As Long,
lpcConnections As Long) As LongConst RAS95_MaxEntryName = 256
Const RAS95_MaxDeviceName = 128
Const RAS_MaxDeviceType = 16Private Type RASCONN95
注释:set dwsize to 412
dwSize As Long
hRasConn As Long
szEntryName(RAS95_MaxEntryName) As Byte
szDeviceType(RAS_MaxDeviceType) As Byte
szDeviceName(RAS95_MaxDeviceName) As Byte
End TypePrivate Sub Command1_Click()
Dim lngRetCode As Long
Dim lpcb As Long
Dim lpcConnections As Long
Dim intArraySize As Integer
Dim intLooper As Integer
ReDim lprasconn95(intArraySize) As RASCONN95
lprasconn95(0).dwSize = 412
lpcb = 256 * lprasconn95(0).dwSize
lngRetCode = RasEnumConnections
(lprasconn95(0), lpcb, lpcConnections)
If lngRetCode = 0 Then
If lpcConnections > 0 Then
For intLooper = 0 To lpcConnections - 1
RasHangUp lprasconn95(intLooper).hRasConn
Next intLooper
Else
MsgBox "没有拨号网络连接!", vbInformation
End If
End If
End Sub---- 运行时,按下按钮就可以断开拨号网络的连接。