Locate a child window, and retrieve its contents

If I know the main window to be of class TBoardWindow (thats what Spy++ says), can I do this then:

// I have the app process ID as dwMyProcess;
HWND hWnd = NULL;
DWORD dwProcess = NULL;
do {
   hWnd = FindWindowEx(NULL,  hWnd, _T("TBoardWindow"), NULL);
   if (!hWnd) break;
   dwProcess = GetWindowThreadProcessId(hWnd,NULL);
   if (dwProcess == dwMyProcess) break;
   else dwProcess=NULL;
} while(true);

To find my window instead of using EnumWindows?

And then I will use the same way to locate the TStringGrid instance. The thing I have no idea how to achieve is how to get the data from the first entry of the TStringGrid control. What API function I have for that? Also, if it is within a tab control and not visible at the moment, would it make any difference when I come to read its data?

Stilgar.

>>how can I get the data of that element - is there an API function that does that?

You will be verywell able to enumerate all the top windows, and locate the window you are looking for and can list all the child windows ie controls etc. But For example using functions like GetWindowText to spy data of edit control which is in another process will not work.  You will have to use the WM_GETTEXT message instead for this.

-MAHESH

>>>> using functions like GetWindowText to spy data of
>>>> edit control which is in another process will not work.  
>>>> You will have to use the WM_GETTEXT message instead for this.

No. Sending a WM_GETTEXT message to a window is the same than calling GetWindowText. In both cases you'll get a char pointer which cannot be interpreted as it comes from a different process environment.  

>>>> The thing I have no idea how to achieve is how to
>>>> get the data from the first entry of the TStringGrid control.
That isn't the main issue. You first need step into the process you want to 'spy' from. There are two techniques: first, you can act like a debugger and read the other process' virtual memory; second, you can 'hook' into the other process by 'installing' a dll function you have to provide in a dll. For the second, the application will call the hook function in the context of its processes, so - if called - you could read char pointers valid for the hooked process.

'debugging' or 'hooking' is both a new game where you need admin priviliges and have to know a lot from the application in question. I hardly can think that it is easy to get a valid pointer of a grid control and have access to some cell contents if not knowing the internals of that control. Note, if the TStringGrid is a active-x all data is accessed via a COM interface and can only be retrieved if you exactly rebuild the needed COM environment. I would think, grabbing a bitmap from the screen and calling some OCR library is more likely to have success than that you want to achieve.

Regards, Alex

>>No. Sending a WM_GETTEXT message to a window is the same than calling GetWindowText

Definately not ! there is differnece .....and my comments here are related to edit, combo and button controls in another process and WM_GETTEXT verywell works with that.

See live Example and  COMPARISON between WM_GETTEXT and GetWindowText:
Article :Getting the Text of a Window in Another Application
http://msdn.microsoft.com/msdnmag/issues/01/08/c/ <=======

**See comparison code  :
http://msdn.microsoft.com/msdnmag/issues/01/08/c/figures.asp <======

-MAHESH

As said in article :

GetWindowText doesn't just send WM_GETTEXT. GetWindowText only sends WM_GETTEXT if the window belongs to the current process. If the window belongs to a different process, GetWindowText does something else.

The documentation is explicit:
If the target window is owned by another process and has a caption, GetWindowText retrieves the window caption text. If the window does not have a caption, the return value is a null string. This behavior is by design.
In other words, you can get the caption from the main window of another process, but not the text of a child window such as an edit control, combobox, or button within it.

-MAHESH