在运行Google地图请求之前检查互联网连接

Question

我有一个包含距离计算的Google地图宏。

如果有互联网连接我只想要这个，否则它应该显示一条消息“没有可用的互联网连接，因此无法进行距离计算”。然后，当用户点击“确定”时，它应该仍然执行除距离计算之外的其余宏，并说明该字段“无可用距离”。

子公式为：

Sub Calculate()
    Application.ScreenUpdating = False

    ' Calculate Macro

    Range("P32:Y32").Select
    ActiveCell.FormulaR1C1 = "=Calculation!R[-17]C[-7]"
    Range("P33:Y34").Select
    ActiveCell.FormulaR1C1 = "=Calculation!R[-16]C[-7]"
    Range("A100").Select

    If IsInternetConnected() = True Then
        If Range("V45") > 1 Then
            Dim wks1 As Worksheet
            Dim blnDone As Boolean, strBaseAddr As String, strGuestAddr As String
            Dim strDist As String, p As Integer
            Set wks1 = Application.ActiveSheet
            blnDone = False
            strBaseAddr = Range("W43")
            wks1.Activate
            wks1.Range("W44").Select

            While Not blnDone
                If Len(ActiveCell) <> 0 Then
                    blnDone = False
                    strDestAddr = ActiveCell
                    strDist = gDistance(strDestAddr, strBaseAddr)
                    p = 1

                    While strDist = "OVER_QUERY_LIMIT" And p <= 5  'if over limit more than 5 times, move on
                        ' try one more time after a pause
                        Application.Wait (Now() + #12:00:02 AM#)  'wait 2 seconds.. should be long enough but at times isn't.
                        strDist = gDistance(strDestAddr, strBaseAddr)
                        p = p + 1
                    Wend

                    If Not IsNumeric(strDist) Then
                        strDist = 0
                    End If

                    Range("X43") = strDist 'distance column
                    ActiveCell.Offset(1, 0).Select 'move down one row
                Else
                    blnDone = True
                End If
            Wend
        Else
            Range("X45") = "No distance available"
        Else
            MsgBox "No internet connection is detected!"
        End If

    End If

    Application.ScreenUpdating = True
 End Sub

和互联网连接的功能是：

Private Declare Function InternetGetConnectedState _
    Lib "wininet.dll" (ByRef dwflags As Long, _
    ByVal dwReserved As Long) As Long

Private Const INTERNET_CONNECTION_MODEM As Long = &H1
Private Const INTERNET_CONNECTION_LAN As Long = &H2
Private Const INTERNET_CONNECTION_PROXY As Long = &H4
Private Const INTERNET_CONNECTION_OFFLINE As Long = &H20

Function IsInternetConnected() As Boolean
    Dim L As Long
    Dim R As Long
    R = InternetGetConnectedState(L, 0&)

    If R = 0 Then
        IsInternetConnected = False
    Else
        If R <= 4 Then
            IsInternetConnected = True
        Else
            IsInternetConnected = False
        End If
    End If
End Function