Visual Basic Text API Routines
SHAutoComplete: Add AutoComplete to a VB Text Box
Posted:   Friday November 26, 1999
Updated:   Monday December 26, 2011
Applies to:   VB4-32, VB5, VB6
Developed with:   VB6, Windows NT4
OS restrictions:   None
Author:   VBnet - Randy Birch


FindWindowEx: Obtain Combo Box Edit Window Handle
GetComboBoxInfo: Obtain Combo Box Edit and List Handles on Win98/NT5
GetVersionEx: Windows Version Info (Wrapper Routines)
Internet Explorer 5 or greater.

IE5 introduced the AutoComplete feature, and its available for both standard VB text boxes and combo boxes using style 0 or 1. The routine here just demonstrates the textbox, but its easily extended to include the combo by passing the handle of the edit control (not the handle to the combo box - see related topics above). When used with the combo box, the AutoComplete dropdown appears in addition to the standard drop down; its data does not replace the dropdown contents.

Use of this API is limited to systems with IE5 or greater, so a handy routine for determining the IE version is included. And although the MSDN states that CoInitialize must be called before using this API, and CoUninitialize called when the edit control has been destroyed, VB takes care of handling this task naturally.

 BAS Module Code

 Form Code
Add a label (Label1), and text box (Text1) and a command button (Command1) to a form, and add the following:

Option Explicit
' Copyright 1996-2011 VBnet/Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
' Distribution: You can freely use this code in your own
'               applications, but you may not reproduce 
'               or publish this code on any web site,
'               online service, or distribute as source 
'               on any media without express permission.
'Flags to control the operation of SHAutoComplete.
'The first four are used to override the Internet
'Explorer registry settings. The user can change
'these settings manually by launching the Internet
'Options property sheet from the Tools menu and
'clicking the Advanced tab. The last five can be
'used to specify which files or URLs will be
'available for auto append or autosuggest operations.

'Ignore registry default and force feature on
Private Const SHACF_AUTOSUGGEST_FORCE_ON  As Long = &H10000000

'Ignore registry default and force feature off.
Private Const SHACF_AUTOSUGGEST_FORCE_OFF  As Long = &H20000000

'Ignore registry default and force feature on. (Also know as AutoComplete)
Private Const SHACF_AUTOAPPEND_FORCE_ON  As Long = &H40000000

'Ignore registry default and force feature off. (Also know as AutoComplete)
Private Const SHACF_AUTOAPPEND_FORCE_OFF  As Long = &H80000000

Private Const SHACF_DEFAULT  As Long = &H0

'Includes the File System as well as the rest
'of the shell (Desktop\My Computer\Control Panel\)
Private Const SHACF_FILESYSTEM  As Long = &H1

'URLs in the User's History
Private Const SHACF_URLHISTORY  As Long = &H2

'URLs in the User's Recently Used list
Private Const SHACF_URLMRU  As Long = &H4


'Identifies the platform for which the DLL was built.
Private Const DLLVER_PLATFORM_WINDOWS As Long = &H1  'Windows 95
Private Const DLLVER_PLATFORM_NT As Long = &H2       'Windows NT

Private Type DllVersionInfo
   cbSize As Long
   dwMajorVersion As Long
   dwMinorVersion As Long
   dwBuildNumber As Long
   dwPlatformID As Long
End Type

Private Declare Function SHAutoComplete Lib "shlwapi" _
  (ByVal hwndEdit As Long, _
   ByVal dwFlags As Long) As Long

Private Declare Function DllGetVersion Lib "shlwapi" _
  (dwVersion As DllVersionInfo) As Long

Private Function GetIEVersion(DVI As DllVersionInfo) As Long
   DVI.cbSize = Len(DVI)
   Call DllGetVersion(DVI)

   GetIEVersion = DVI.dwMajorVersion
End Function

Private Function GetIEVersionString() As String
   Dim DVI As DllVersionInfo
   DVI.cbSize = Len(DVI)
   Call DllGetVersion(DVI)

   GetIEVersionString = "Internet Explorer " & _
                        DVI.dwMajorVersion & "." & _
                        DVI.dwMinorVersion & "." & _
End Function

Private Sub Command1_Click()

   Dim DVI As DllVersionInfo

   If GetIEVersion(DVI) >= 5 Then
     'Turn on auto-complete
      Call SHAutoComplete(Text1.hWnd, SHACF_DEFAULT)
     'update the captions and set focus to the textbox
      Command1.Caption = "SHAutoComplete is On"
      Command1.Enabled = False
      Text1.SelStart = Len(Text1.Text)
      MsgBox "Sorry ... you need IE5 to use this demo", vbExclamation
   End If
End Sub

Private Sub Form_Load()

  'dim a DllVersionInfo type
   Dim DVI As DllVersionInfo

  'display the version of Shlwapi
   Label1.Caption = "Using Shlwapi.dll for " & GetIEVersionString
  'if not 5 or greater, can't do it
   Command1.Enabled = GetIEVersion(DVI) >= 5
   Command1.Caption = "SHAutoComplete is Off"

End Sub


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