Q200027: HOWTO: Determine If IE Is Offline from an ActiveX Document

Article: Q200027
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,4.01,4.01 SP1,4.01 SP2,5,5.0,5.5,6.0
Operating System(s): 
Keyword(s): kbActiveDocs kbInternet kbVBp kbVC500 kbVC600 kbie401sp1 kbie401sp2 kbGrpDSInet kbie500
Last Modified: 20-JUL-2001

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The information in this article applies to:

- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Internet Explorer (Programming) versions 4.0, 4.01, 4.01 SP1, 4.01 SP2, 5, 5.5 
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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 determine 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:

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Keywords          : kbActiveDocs kbInternet kbVBp kbVC500 kbVC600 kbie401sp1 kbie401sp2 kbGrpDSInet kbie500 kbie550 
Technology        : kbVBSearch kbIEsearch kbAudDeveloper kbZNotKeyword6 kbSDKIESearch kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600 kbIE500Search kbSDKIE400 kbSDKIE401 kbSDKIE401SP1 kbSDKIE401SP2 kbSDKIE500 kbSDKIE550 kbIE550Search
Version           : WINDOWS:4.0,4.01,4.01 SP1,4.01 SP2,5,5.0,5.5,6.0
Issue type        : kbhowto

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