PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:4.0 5.0 7.0 97
OPER/SYS:WINDOWS
KEYWORDS:APrgWindow kbcode vb432 vb4win vb5all vb5howto VBKBWinAPI kbhowto
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The information in this article applies to:
- Microsoft Visual Basic Control Creation, Learning, Professional, and
Enterprise Editions for Windows, version 5.0
- Microsoft Visual Basic Standard, Professional, and Enterprise Editions,
32-bit only, for Windows, version 4.0
- Microsoft Access versions 7.0, 97
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SUMMARY
=======
When trying to determine whether a child window of an application is open,
you need to know whether it is a child of the main application window, a
grandchild, or an independent window. This article provides a method of
creating a hierarchical listing of all currently open windows and their
window class names, making it easier navigating a program's window
hierarchy.
MORE INFORMATION
================
WARNING: Microsoft provides code examples for illustration only, without
warranty either expressed or implied, including but not limited to the
implied warranties of merchantability and/or fitness for a particular
purpose. This code is provided 'as is' and Microsoft does not guarantee
that the following code can be used in all situations. Microsoft does not
support modifications of the code to suit customer requirements for a
particular purpose.
Step-by-Step Example
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1. Create a new project with a Form and a Module.
2. Add the following controls to the form:
Control Name Property Value
------------------------------------------------
Command button Command1
Text box Text1 MultiLine TRUE
Text box Text1 Scrollbars 2- Vertical
NOTE: The MultiLine property only applies to Visual Basic.
3. Type the following code into the module:
Option Explicit
Public Const GW_CHILD = 5
Public Const GW_HWNDNEXT = 2
Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, _
ByVal wCmd As Long) As Long
Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
(ByVal hwnd As Long, ByVal lpString As String, _
ByVal cch As Long) As Long
Declare Function GetTopWindow Lib "user32" _
(ByVal hwnd As Long) As Long
Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
(ByVal hwnd As Long, ByVal lpClassName As String, _
ByVal nMaxCount As Long) As Long
4. Add the following code to the form's module:
Sub AddChildWindows(ByVal hwndParent As Long, ByVal Level As Long)
Dim WT As String, CN As String, Length As Long, hwnd As Long
If Level = 0 Then
hwnd = hwndParent
Else
hwnd = GetWindow(hwndParent, GW_CHILD)
End If
Do While hwnd <> 0
WT = Space(256)
Length = GetWindowText(hwnd, WT, 255)
WT = Left$(WT, Length)
CN = Space(256)
Length = GetClassName(hwnd, CN, 255)
CN = Left$(CN, Length)
Me!Text1 = Me!Text1 & vbCrLf & String(2 * Level, ".") _
& WT & " (" & CN & ")"
AddChildWindows hwnd, Level + 1
hwnd = GetWindow(hwnd, GW_HWNDNEXT)
Loop
End Sub
Sub Command1_Click()
Dim hwnd As Long
hwnd = GetTopWindow(0)
If hwnd <> 0 Then
AddChildWindows hwnd, 0
End If
End Sub
5. Visual Basic only: Run the project.
Access only: Open the form.
6. Click the CommandButton. The text box will be filled with a list of
windows and their children arranged in a hierarchical order. The class
name will follow the window name, such as:
MainWindowName (WindowClass)
..ChildWindowName (WindowClass)
....GrandchildWindowName (WindowClass)
NOTE: Not all windows will have a name but all will have a Window Class.
REFERENCES
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Microsoft Windows SDK
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Keywords : APrgWindow kbcode vb432 vb4win vb5all vb5howto VBKBWinAPI kbhowto
Version : 4.0 5.0 7.0 97
Platform : WINDOWS
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THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO
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SO THE FOREGOING LIMITATION MAY NOT APPLY.
Copyright Microsoft Corporation 1997.