HOWTO: Tell if Internet Explorer is Offline from an ActiveX Doc

ID: Q200027


The information in this article applies to:


SUMMARY

When developing Internet applications, developers need to account for end users with a wide variety of system environments with different ways of connecting to the Internet. This ActiveX Document sample code demonstrates how to tell if Internet Explorer is offline.


MORE INFORMATION

Use the following sample code to determine if Internet Explorer is offline:

  1. Start a new ActiveX Document project. UserDocument1 is added by default.


  2. Add the following code to the general declarations section of UserDocument1:
    
    Dim bOffline As Boolean
    
    Private Function get_Offline() As Boolean ' (VARIANT_BOOL * bOffline)
     Dim hr As Long
     Dim ci As INTERNET_CONNECTED_INFO
     Dim ci_len As Long
     ci_len = 8
     Dim ret As Long
    
     ret = InternetQueryOption(0&, INTERNET_OPTION_CONNECTED_STATE, _
            ci, ci_len)
    get_Offline = Not ((ci.dwConnectedState And INTERNET_STATE_CONNECTED) = 
    INTERNET_STATE_CONNECTED)
    End Function
    
    Private Sub put_Offline(bOffline As Boolean)
      Dim hr As Long
      Dim ci As INTERNET_CONNECTED_INFO
      Dim ret As Long
      If bOffline Then
         ci.dwConnectedState = INTERNET_STATE_DISCONNECTED_BY_USER
         ci.dwFlags = ISO_FORCE_DISCONNECTED
      Else
         ci.dwConnectedState = INTERNET_STATE_CONNECTED
      End If
    
      ret = InternetSetOption(0&, INTERNET_OPTION_CONNECTED_STATE, _
                   ci, LenB(ci))
    End Sub 


  3. Add a Command button to UserDocument1 and insert this code:
    
    Private Sub Command1_Click()
       MsgBox "Offline = " & get_Offline()
    End Sub 


  4. Add a Command button to form1 and insert this code.
    
    Private Sub Command2_Click()
       put_Offline True
    End Sub 


  5. Add a standard module to the project and insert this code.
    
       Option Explicit
       Public Type INTERNET_CONNECTED_INFO
          dwConnectedState As Long
          dwFlags As Long
       End Type
    
    
       Public Declare Function InternetSetOption Lib "wininet.dll" Alias _
         "InternetSetOptionA" (ByVal hInternet As Long, _
           ByVal lOption As Long, ByRef sBuffer As Any, _
             ByVal lBufferLength As Long) As Integer
    
    ' Queries an Internet option on the specified handle
       Public Declare Function InternetQueryOption Lib "wininet.dll" Alias _
        "InternetQueryOptionA" (ByVal hInternet As Long, _
           ByVal lOption As Long, ByRef sBuffer As Any, _
           ByRef lBufferLength As Long) As Integer
    
       Public Const INTERNET_OPTION_CONNECTED_STATE = 50
       Public Const INTERNET_STATE_CONNECTED = 1
    
    ' // disconnected from network
        Public Const INTERNET_STATE_DISCONNECTED = 2
    ' 0x00000010    //  disconnected by user request
        Public Const INTERNET_STATE_DISCONNECTED_BY_USER = &H10
    '// no network requests being made (by Wininet)
        Public Const INTERNET_STATE_IDLE = &H100
    '// network requests being made (by  Wininet)
        Public Const INTERNET_STATE_BUSY = &H200
    '// 
    '// ISO_FORCE_DISCONNECTED -
    '// if set when putting Wininet into disconnected mode,
    '// all outstanding requests will be aborted with a cancelled error
    '// 
    
    Public Const ISO_FORCE_DISCONNECTED = 1
     


  6. Save Project and press F5 to test.


Additional query words: kbDSupport


Keywords          : kbActiveDocs kbInternet kbVBp kbVC500 kbVC600 kbIE401sp1 kbIE401sp2 kbGrpInet kbIE500 
Version           : WINDOWS:4.0,4.01,4.01 SP1,4.01 SP2,5.0,6.0
Platform          : WINDOWS 
Issue type        : kbhowto 

Last Reviewed: May 8, 1999