如何检测是否已连接到Internet？

声明：

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

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

程序：

Private Sub main()

  If IsConnected = True Then

    MsgBox "已连接到Internet！", vbInformation, "提示"

  Else

    MsgBox "未连接到Internet！", vbInformation, "提示"

  End If

End Sub

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 "产生错误！", vbInformation, "提示"

    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