156.htm

vb功能实例介绍。详细、很好的实例说明。

<p>检测是否连接到Internet</p>
<p></p>
<p>Private Declare Function RasEnumConnections Lib "RasApi32.dll" Alias "RasEnumConnectionsA" (lpRasCon As Any, lpcb As Long, lpcConnections As Long) As Long</p>
<p>Private Declare Function RasGetConnectStatus Lib "RasApi32.dll" Alias "RasGetConnectStatusA" (ByVal hRasCon As Long, lpStatus As Any) As Long</p>
<p>`</p>
<p>Private Const RAS95_MaxEntryName = 256</p>
<p>Private Const RAS95_MaxDeviceType = 16</p>
<p>Private Const RAS95_MaxDeviceName = 32</p>
<p>`</p>
<p>Private Type RASCONN95</p>
<p>    dwSize As Long</p>
<p>    hRasCon As Long</p>
<p>    szEntryName(RAS95_MaxEntryName) As Byte</p>
<p>    szDeviceType(RAS95_MaxDeviceType) As Byte</p>
<p>    szDeviceName(RAS95_MaxDeviceName) As Byte</p>
<p>End Type</p>
<p>`</p>
<p>Private Type RASCONNSTATUS95</p>
<p>    dwSize As Long</p>
<p>    RasConnState As Long</p>
<p>    dwError As Long</p>
<p>    szDeviceType(RAS95_MaxDeviceType) As Byte</p>
<p>    szDeviceName(RAS95_MaxDeviceName) As Byte</p>
<p>End Type</p>
<p></p>
<p>`A call to the function IsConnected returns true if the computer has established a connection to the internet.</p>
<p></p>
<p>Private Function IsConnected() As Boolean</p>
<p>Dim TRasCon(255) As RASCONN95</p>
<p>Dim lg As Long</p>
<p>Dim lpcon As Long</p>
<p>Dim RetVal As Long</p>
<p>Dim Tstatus As RASCONNSTATUS95</p>
<p>`</p>
<p>TRasCon(0).dwSize = 412</p>
<p>lg = 256 * TRasCon(0).dwSize</p>
<p>`</p>
<p>RetVal = RasEnumConnections(TRasCon(0), lg, lpcon)</p>
<p>If RetVal <> 0 Then</p>
<p>                    MsgBox "ERROR"</p>
<p>                    Exit Function</p>
<p>                    End If</p>
<p>`</p>
<p>Tstatus.dwSize = 160</p>
<p>RetVal = RasGetConnectStatus(TRasCon(0).hRasCon, Tstatus)</p>
<p>If Tstatus.RasConnState = &H2000 Then</p>
<p>                         IsConnected = True</p>
<p>                         Else</p>
<p>                         IsConnected = False</p>
<p>                         End If</p>
<p></p>
<p>End Function</p>
<p></p>
<p></p>
<p>Private Sub Command1_Click()</p>
<p>  If IsConnected = True Then</p>
<p>    MsgBox "连接到Internet", vbInformation + vbOKOnly, "泰山"</p>
<p>  Else</p>
<p>    MsgBox "没有连接到Internet", vbInformation + vbOKOnly, "泰山"</p>
<p>  End If</p>
<p>End Sub </p>