Click here to Skip to main content
Click here to Skip to main content

Capturing Window Controls and Modifying their properties

, 19 Feb 2005 GPL3
Rate this:
Please Sign up or sign in to vote.
A Spy tool program like MS Spy++ that lets you capture window controls and modify their properties. Useful for learning window handles and their properties.

Sample Image - windowspy.gif

Introduction

I was interested to have a tool such as Spy++ in Microsoft Visual Studio, but I'd like that the tool can modify window controls. For instance, some times, we need to enable some inactive controls in a program during run-time. MS Spy++ does not have any facilities to do this, and so I made it by myself.

This program is useful to obtain a window handle, caption, class name, style, and size. Moreover, it facilitates changing caption name, style, and extended style of victim window control in run-time load.

The application is a Win32 project without using MFC. It hooks the target window by WindowFromPoint() user32 API. There is an algorithm to seek on child and parent window to capture child windows inside a program by using GetWindowRect() and GetWindow() in a tricky way. It applies GetWindowLong() to obtain window properties and SetWindowLong() to modify them.

Hooking target window

We can hook victim window through WM_MOUSEMOVE mouse event:

case WM_MOUSEMOVE:
if (bSeeking)
{
  HWND hWindowUnderTheMouse;
  //HWND hWindowUnderTheMouseChild;
  points = MAKEPOINTS(lParam); 
  point.x=points.x;
  point.y=points.y;
  ClientToScreen(hDlg,&point);
  hWindowUnderTheMouse = WindowFromPoint(point);
  if((hwndMain==hWindowUnderTheMouse)||
    (hwndMain==GetParent(hWindowUnderTheMouse)))
  {
    break;
  }
  //------------------------------
  hChildFound=NULL;
  SeekDumpWindow(hWindowUnderTheMouse,point);
  if((IsWindow(hChildFound))&&(hChildFound!=NULL))
  {
    hWindowUnderTheMouse=hChildFound;
  }
  //------------------------------
  if(hWindowUnderTheMouse != hSeekedWindow)
  {
    //
    FrameWindow(hSeekedWindow);
    hSeekedWindow = hWindowUnderTheMouse;
    FrameWindow(hSeekedWindow);
    // update the twin window
    strcpy(szSeekedWindow,"0x");
    _itoa((DWORD)hSeekedWindow,szSeekedWindow+2,16);
    CharUpperBuff(szSeekedWindow+2,(DWORD)strlen(szSeekedWindow));
    SetDlgItemText(hDlg,IDC_WINDOWHANDLE,szSeekedWindow);
    GetWindowInfo(hSeekedWindow);
  }
}
else
{
  points = MAKEPOINTS(lParam); 
  point.x=points.x;
  point.y=points.y;
}
break;

It seeks the correct window target by searching through its parent and its children by SeekDumpWindow() which is defined in <DumpSeek.h> inside the program.

Modifying target window

It is very easy to modify the victim window by its handle. If you have the window handle, you can obtain and change styles very easily by GetWindowLong() and SetWindowLong() and also window caption by using SetWindowText() and SendDlgItemMessage(). By looking inside UpdateFlags() in the program, you will find the code which performs this to modify the target window:

if(TopMost) 
{
  dwExtendedStyle|=WS_EX_TOPMOST; 
  SetWindowPos(hHandle, 
  HWND_TOPMOST, 0, 0, 0, 0,
  SWP_NOSIZE|SWP_NOMOVE);
}
else
{
  dwExtendedStyle&=~WS_EX_TOPMOST;
  SetWindowPos(hHandle, 
  HWND_NOTOPMOST, 0, 0, 0, 0,
  SWP_NOSIZE|SWP_NOMOVE);
}
//----------------------------------------------
if(BACKdwID!=dwID) SetWindowLong(hHandle, GWL_ID, dwID);
if(BACKdwStyle!=dwStyle)SetWindowLong(hHandle, GWL_STYLE, dwStyle);
if(BACKdwExtendedStyle=dwExtendedStyle)
SetWindowLong(hHandle, GWL_EXSTYLE, dwExtendedStyle);
if(Visible)
{
  ShowWindow(hHandle,SW_HIDE);
  ShowWindow(hHandle,SW_SHOW);
}
else
{
  ShowWindow(hHandle,SW_SHOW);
  ShowWindow(hHandle,SW_HIDE);
}
UpdateWindow(GetParent(hHandle));

The code to change caption depends on the type of window control. To change caption of Edit Control and Box Control, it has to use SendDlgItemMessage() instead of SetWindowText() in other window controls:

if((strstr(_szClassName,"EDIT")==NULL)&&(strstr(_szClassName,"BOX")==NULL))
{
  SetWindowText(hHandle,szTitle);
}
else
{
  HWND hWndParent=GetParent(hHandle);
  SendDlgItemMessage(hWndParent,dwID,WM_SETTEXT,0,(LPARAM)szTitle);
}

Conclusion

I hope this tool clarifies window classes and their manipulation for people who are beginners in this field. This would be an introduction to make window Spy tools and work with handles.

Eventually, I should appreciate you if you would kindly take the time to mention your ideas, suggestions, and any bugs you may find in this program.

License

This article, along with any associated source code and files, is licensed under The GNU General Public License (GPLv3)

Share

About the Author

Ashkbiz Danehkar
Other
Australia Australia
No Biography provided

Comments and Discussions

 
QuestionCan it capture a label in vb6 program? Pinmemberpctimhk30-Sep-06 8:24 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web02 | 2.8.141030.1 | Last Updated 19 Feb 2005
Article Copyright 2005 by Ashkbiz Danehkar
Everything else Copyright © CodeProject, 1999-2014
Layout: fixed | fluid