当然访问的后台数据库不在是本地或者局域网，那我们需要判断当前电脑是否有连接到互联网，代码很简单，具体做方法如下：
Public Declare Function InternetGetConnectedState Lib "wininet.dll" (ByRef dwflags As Long, ByVal dwReserved As Long) As Long
Public Function IsNetConnectOnLine() As Boolean
'不需要标志值，如果有其他类型返回True
IsNetConnectOnLine = InternetGetConnectedState(0&, 0&)
End Function
Private Sub Command56_Click()
If IsNetConnectOnLine Then
MsgBox "已连接"
else
msgbox"未连接"
End If
End Sub
示 例:
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