Visual Basic Programming Code Examples

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Finding Out If A Computer Is Connected To The Internet



Finding Out If A Computer Is Connected To The Internet

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


Public Function IsConnected() As Boolean
    'Dimension Variables.
    Dim TRasCon(255) As RASCONN95
    Dim lg As Long
    Dim lpcon As Long
    Dim RetVal As Long
    Dim Tstatus As RASCONNSTATUS95

    'Find out whether the target computer is connected.
    TRasCon(0).dwSize = 412
    lg = 256 * TRasCon(0).dwSize

    RetVal = RasEnumConnections(TRasCon(0), lg, lpcon)

    If RetVal <> 0 Then
        'An error has occured.  Handle it here.
        Exit Function
    End If

    Tstatus.dwSize = 160
    RetVal = RasGetConnectStatus(TRasCon(0).hRasCon, Tstatus)

    'Return whether we are connected or not.
    If Tstatus.RasConnState = &H2000 Then
        IsConnected = True
    Else
        IsConnected = False
    End If
End Function