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How To Determine If Internet Explorer Is Offline from an ActiveX Document

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Article ID:200027
Last Review:July 1, 2004
Revision:2.1
This article was previously published under Q200027

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.
APPLIES TO
•Microsoft Visual Basic 5.0 Professional Edition
•Microsoft Visual Basic 6.0 Professional Edition
•Microsoft Visual Basic 5.0 Enterprise Edition
•Microsoft Visual Basic 6.0 Enterprise Edition
•Microsoft Internet Explorer 4.0 128-Bit Edition
•Microsoft Internet Explorer 4.01 Service Pack 2
•Microsoft Internet Explorer 4.01 Service Pack 1
•Microsoft Internet Explorer 5.0
•Microsoft Internet Explorer 5.5

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Keywords: 
kbhowto kbactivedocs KB200027

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