The information in this article applies to:
- Microsoft Visual Basic Learning, Professional, and Enterprise Editions
for Windows, version 5.0
- Microsoft Visual Basic Standard, Professional, and Enterprise Editions,
16-bit and 32-bit, for Windows, version 4.0
- Standard and Professional Editions of Microsoft Visual Basic for
Windows, version 3.0
SUMMARY
You could use SPY.EXE, which comes with Microsoft Visual C/C++, to get
information such as a window's class name. However, this article shows by
example how you can create your own Visual Basic application that does the
same thing; displays a window's class name along with several other
attributes. For example, you might need a window's class name for use in a
function in the Microsoft Windows Application Programming Interface
(Windows API).
MORE INFORMATION
This example uses several functions from the Windows API to get information
about the window the cursor is currently over. First, the routine calls
GetCursorPos to get the current position of the cursor. Then it calls
WindowFromPoint to get the handle to the window the cursor is currently
over. Then it calls several other functions in the Windows API to get
specific information pertaining to the window.
The example finds the following information about the window:
- Window Handle
- Window Text
- Window Class Name
- Window Style
- Window ID Number
- Parent Window Handle (if applicable)
- Parent Window Text (if applicable)
- Parent Window Class Name (if applicable)
- Module File Name
The example can be easily expanded to get other window attributes by
calling appropriate functions in the Windows API.
Step-by-Step Example
THE FOLLOWING SECTION APPLIES TO VISUAL BASIC 4.0 AND 5.0 ONLY:
This example creates a Visual Basic program that produces results similar
to those produced by SPY.EXE, and makes use of conditional compilation so
that the program can be run in either 16-bit or 32-bit editions of Visual
Basic.
NOTE: Although the code below works in Visual Basic 5.0, it not
necessary to use the conditional compilation (#If Win16, #ElseIf Win32)
in Visual Basic 5.0 since it requires 32-bit. As a result, you can
shorten the code below by using only the 32-bit declarations.
- Start a new project in Visual Basic. Form1 is created by default.
- Add the following declarations to the general declarations section of
Form1:
#If Win16 Then
Private Declare Sub GetCursorPos Lib "User" (lpPoint As Long)
Private Declare Function WindowFromPoint Lib "User" (ByVal ptScreen _
As Any) As Integer
Private Declare Function GetModuleFileName Lib "Kernel" (ByVal _
hModule As Integer, ByVal lpFileName As String, ByVal nSize As _
Integer) As Integer
Private Declare Function GetWindowWord Lib "User" (ByVal hwnd As _
Integer, ByVal nIndex As Integer) As Integer
Private Declare Function GetWindowLong Lib "User" (ByVal hwnd As _
Integer, ByVal nIndex As Integer) As Long
Private Declare Function GetParent Lib "User" (ByVal hwnd As _
Integer) As Integer
Private Declare Function GetClassName Lib "User" (ByVal hwnd As _
Integer, ByVal lpClassName As String, ByVal nMaxCount As _
Integer) As Integer
Private Declare Function GetWindowText Lib "User" (ByVal hwnd As _
Integer, ByVal lpString As String, ByVal aint As Integer) As _
Integer
#ElseIf Win32 Then
Private Type POINTAPI
x As Long
y As Long
End Type
Private Declare Function GetCursorPos Lib "User32" (lpPoint As _
POINTAPI) As Long
Private Declare Function WindowFromPointXY Lib "User32" Alias _
"WindowFromPoint" (ByVal xPoint As Long, ByVal yPoint As Long) _
As Long
Private Declare Function GetModuleFileName Lib "kernel32" Alias _
"GetModuleFileNameA" (ByVal hModule As Long, ByVal lpFileName As _
String, ByVal nSize As Long) As Long
Private Declare Function GetWindowWord Lib "User32" (ByVal hwnd As _
Long, ByVal nIndex As Long) As Integer
Private Declare Function GetWindowLong Lib "User32" Alias _
"GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As _
Long
Private Declare Function GetParent Lib "User32" (ByVal hwnd As _
Long) As Long
Private Declare Function GetClassName Lib "User32" Alias _
"GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As _
String, ByVal nMaxCount As Long) As Long
Private Declare Function GetWindowText Lib "User32" Alias _
"GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, _
ByVal cch As Long) As Long
#End If
Const GWW_HINSTANCE = (-6)
Const GWW_ID = (-12)
Const GWL_STYLE = (-16)
- Add a timer control (Timer1) to the form.
- Set the interval property of the timer to 200.
- Add the following code to timer's timer event:
Sub Timer1_Timer()
#If Win16 Then
Dim ptCursor As Long
Dim sWindowText As String * 100
Dim sClassName As String * 100
Dim hWndOver As Integer
Dim hWndParent As Integer
Dim sParentClassName As String * 100
Dim wID As Integer
Dim lWindowStyle As Long
Dim hInstance As Integer
Dim sParentWindowText As String * 100
Dim sModuleFileName As String * 100
Static hWndLast As Integer
Call GetCursorPos(ptCursor) ' Get cursor position
hWndOver = WindowFromPoint(ptCursor) ' Get window cursor is over
If hWndOver <> hWndLast Then ' If changed update display
hWndLast = hWndOver ' Save change
Cls ' Clear the form
Print "Window Handle: &H"; Hex(hWndOver) ' Display window handle
r = GetWindowText(hWndOver, sWindowText, 100) ' Window text
Print "Window Text: " & Left(sWindowText, r)
r = GetClassName(hWndOver, sClassName, 100) ' Window Class
Print "Window Class Name: "; Left(sClassName, r)
lWindowStyle = GetWindowLong(hWndOver, GWL_STYLE) ' Window Style
Print "Window Style: &H"; Hex(lWindowStyle)
' Get handle of parent window:
hWndParent = GetParent(hWndOver)
' If there is a parent get more info:
If hWndParent <> 0 Then
' Get ID of window:
wID = GetWindowWord(hWndOver, GWW_ID)
Print "Window ID Number: &H"; Hex(wID)
Print "Parent Window Handle: &H"; Hex(hWndParent)
' Get the text of the Parent window:
r = GetWindowText(hWndParent, sParentWindowText, 100)
Print "Parent Window Text: " & Left(sParentWindowText, r)
' Get the class name of the parent window:
r = GetClassName(hWndParent, sParentClassName, 100)
Print "Parent Window Class Name: "; Left(sParentClassName, r)
Else
' Update fields when no parent:
Print "Window ID Number: N/A"
Print "Parent Window Handle: N/A"
Print "Parent Window Text : N/A"
Print "Parent Window Class Name: N/A"
End If
' Get window instance:
hInstance = GetWindowWord(hWndOver, GWW_HINSTANCE)
' Get module file name:
r = GetModuleFileName(hInstance, sModuleFileName, 100)
Print "Module: "; Left(sModuleFileName, r)
End If
#ElseIf Win32 Then
Dim pt32 As POINTAPI
Dim ptx As Long
Dim pty As Long
Dim sWindowText As String * 100
Dim sClassName As String * 100
Dim hWndOver As Long
Dim hWndParent As Long
Dim sParentClassName As String * 100
Dim wID As Long
Dim lWindowStyle As Long
Dim hInstance As Long
Dim sParentWindowText As String * 100
Dim sModuleFileName As String * 100
Static hWndLast As Long
Call GetCursorPos(pt32) ' Get cursor position
ptx = pt32.x
pty = pt32.y
hWndOver = WindowFromPointXY(ptx, pty) ' Get window cursor is over
If hWndOver <> hWndLast Then ' If changed update display
hWndLast = hWndOver ' Save change
Cls ' Clear the form
Print "Window Handle: &H"; Hex(hWndOver) ' Display window handle
r = GetWindowText(hWndOver, sWindowText, 100) ' Window text
Print "Window Text: " & Left(sWindowText, r)
r = GetClassName(hWndOver, sClassName, 100) ' Window Class
Print "Window Class Name: "; Left(sClassName, r)
lWindowStyle = GetWindowLong(hWndOver, GWL_STYLE) ' Window Style
Print "Window Style: &H"; Hex(lWindowStyle)
' Get handle of parent window:
hWndParent = GetParent(hWndOver)
' If there is a parent get more info:
If hWndParent <> 0 Then
' Get ID of window:
wID = GetWindowWord(hWndOver, GWW_ID)
Print "Window ID Number: &H"; Hex(wID)
Print "Parent Window Handle: &H"; Hex(hWndParent)
' Get the text of the Parent window:
r = GetWindowText(hWndParent, sParentWindowText, 100)
Print "Parent Window Text: " & Left(sParentWindowText, r)
' Get the class name of the parent window:
r = GetClassName(hWndParent, sParentClassName, 100)
Print "Parent Window Class Name: "; Left(sParentClassName, r)
Else
' Update fields when no parent:
Print "Window ID Number: N/A"
Print "Parent Window Handle: N/A"
Print "Parent Window Text : N/A"
Print "Parent Window Class Name: N/A"
End If
' Get window instance:
hInstance = GetWindowWord(hWndOver, GWW_HINSTANCE)
' Get module file name:
r = GetModuleFileName(hInstance, sModuleFileName, 100)
Print "Module: "; Left(sModuleFileName, r)
End If
#End If
End Sub
- Save the project files.
- Run the program, and move the mouse over different windows. You will see
the field values change as you move the mouse over different windows.
Step-by-Step Example
THE FOLLOWING SECTION APPLIES TO VISUAL BASIC 3.0 ONLY:
This example creates a Visual Basic program that produces results similar
to those produced by SPY.EXE.
- Start a new project in Visual Basic. Form1 is created by default.
- Add the following declarations to the general declarations section of
Form1:
'VB3Line: Enter the following lines as one line
Declare Sub GetCursorPos Lib "User" (lpPoint As Long)
Declare Function WindowFromPoint Lib "User" (ByVal ptScreen As Any) As
Integer
Declare Function GetModuleFileName Lib "Kernel" (ByVal hModule As
Integer, ByVal lpFilename As String, ByVal nSize As Integer) As
Integer
Declare Function GetWindowWord Lib "User" (ByVal hWnd As Integer, ByVal
nIndex As Integer) As Integer
Declare Function GetWindowLong Lib "User" (ByVal hWnd As Integer, ByVal
nIndex As Integer) As Long
Declare Function GetParent Lib "User" (ByVal hWnd As Integer) As Integer
Declare Function GetClassName Lib "User" (ByVal hWnd As Integer, ByVal
lpClassName As String, ByVal nMaxCount As Integer) As Integer
Declare Function GetWindowText Lib "User" (ByVal hWnd As Integer, ByVal
lpString As String, ByVal aint As Integer) As Integer
Const GWW_HINSTANCE = (-6)
Const GWW_ID = (-12)
Const GWL_STYLE = (-16)
- Add a timer control (Timer1) to the form.
- Set the interval property of the timer to 200.
- Add the following code to timer's timer event:
Sub Timer1_Timer()
Dim ptCursor As Long
Dim sWindowText As String * 100
Dim sClassName As String * 100
Dim hWndOver As Integer
Dim hWndParent As Integer
Dim sParentClassName As String * 100
Dim wID As Integer
Dim lWindowStyle As Long
Dim hInstance As Integer
Dim sParentWindowText As String * 100
Dim sModuleFileName As String * 100
Static hWndLast As Integer
Call GetCursorPos(ptCursor) ' Get cursor position
hWndOver = WindowFromPoint(ptCursor) ' Get window cursor is over
If hWndOver <> hWndLast Then ' If changed update display
hWndLast = hWndOver ' Save change
Cls ' Clear the form
Print "Window Handle: &H"; Hex(hWndOver) ' Display window handle
r = GetWindowText(hWndOver, sWindowText, 100) ' Window text
Print "Window Text: " & Left(sWindowText, r)
r = GetClassName(hWndOver, sClassName, 100) ' Window Class
Print "Window Class Name: "; Left(sClassName, r)
lWindowStyle = GetWindowLong(hWndOver, GWL_STYLE) ' Window Style
Print "Window Style: &H"; Hex(lWindowStyle)
' Get handle of parent window:
hWndParent = GetParent(hWndOver)
' If there is a parent get more info:
If hWndParent <> 0 Then
' Get ID of window:
wID = GetWindowWord(hWndOver, GWW_ID)
Print "Window ID Number: &H"; Hex(wID)
Print "Parent Window Handle: &H"; Hex(hWndParent)
' Get the text of the Parent window:
r = GetWindowText(hWndParent, sParentWindowText, 100)
Print "Parent Window Text: " & Left(sParentWindowText, r)
' Get the class name of the parent window:
r = GetClassName(hWndParent, sParentClassName, 100)
Print "Parent Window Class Name: "; Left(sParentClassName, r)
Else
' Update fields when no parent:
Print "Window ID Number: N/A"
Print "Parent Window Handle: N/A"
Print "Parent Window Text : N/A"
Print "Parent Window Class Name: N/A"
End If
' Get window instance:
hInstance = GetWindowWord(hWndOver, GWW_HINSTANCE)
' Get module file name:
r = GetModuleFileName(hInstance, sModuleFileName, 100)
Print "Module: "; Left(sModuleFileName, r)
End If
End Sub
- Save the project files.
- Run the program, and move the mouse over different windows. You will see
the field values change as you move the mouse over different windows.
REFERENCES
- Microsoft Windows Software Development Kit (SDK)
- Microsoft Visual Basic for Windows SDK Help file
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