Different results from EnumChildWindows vs FindWindowEx

[Chris J]

Hi-

I'm relatively new to the win32 API realm. I've been using the API to try
and find controls within a top-level window. I tried using FindWindowEx to
find the "Exit" button from the window, but it always returns NULL. I finally
set up a call to EnumChildWindows, and I can find the control that way.

Are there conditions under which these two methods are expected to return
different results like this? The window that I'm getting information about is
a .NET application.

Thanks.

[Alex Blekhman]

I've been using the API to try and find controls within a
top-level window. I tried using FindWindowEx to find the "Exit"
button from the window, but it always returns NULL. I finally
set up a call to EnumChildWindows, and I can find the control
that way.

Could you post some code, please? Also, ensure that you give
correct parent window handle to `FindWindowEx' functon.

Alex

[Chris J]

I'm actually writing GUI testing code in Ruby, using a Win32 API module that
wraps actual API calls. However, I reproduced the same issue in C++. The C++
code appends output to a list box in a GUI:

BOOL CALLBACK EnumChildProc(HWND hwndChild, LPARAM lParam)
{
HWND hParent = (HWND)lParam;

int txtLen;

int len = GetWindowTextLength(hwndChild);
if(len > 0)
{
char* buf;

buf = (char*)GlobalAlloc(GPTR, len + 1);
GetWindowText(hwndChild, buf, len + 1);

if (strlen(buf) > 0) {
int index = SendDlgItemMessage(hParent, IDC_MAIN_LIST, LB_ADDSTRING,
0, (LPARAM)buf);
}

GlobalFree((HANDLE)buf);
}
return TRUE;
}


Here's the code that calls EnumChildWindows and FindWindowEx

HWND hTopWindow;
HWND hExitBtn;
char* message;
// Find my application's window and enumerate its children.
hTopWindow = FindWindow(NULL,"My Application");

if (hTopWindow > 0) {
EnumChildWindows( hTopWindow, EnumChildProc, hwnd );
}

// Now try to find the Exit button explicitly.
hExitBtn = FindWindowEx(hTopWindow, 0, NULL, "e&xit");
message = (hExitBtn > 0) ? "Exit button was found." :
"Exit button NOT found.";

SendDlgItemMessage(hwnd, IDC_MAIN_LIST, LB_ADDSTRING, 0,
(LPARAM)message);


EnumChildProc displays "E&xit" as one of the child control's text, but
FindWindowEx does not find the control.

Post by Alex Blekhman
Could you post some code, please? Also, ensure that you give
correct parent window handle to `FindWindowEx' functon.
Alex

[Norman Bullen]

Post by Chris J
I'm actually writing GUI testing code in Ruby, using a Win32 API module that
wraps actual API calls. However, I reproduced the same issue in C++. The C++
BOOL CALLBACK EnumChildProc(HWND hwndChild, LPARAM lParam)
{
HWND hParent = (HWND)lParam;
int txtLen;
int len = GetWindowTextLength(hwndChild);
if(len > 0)
{
char* buf;
buf = (char*)GlobalAlloc(GPTR, len + 1);
GetWindowText(hwndChild, buf, len + 1);
if (strlen(buf) > 0) {
int index = SendDlgItemMessage(hParent, IDC_MAIN_LIST, LB_ADDSTRING,
0, (LPARAM)buf);
}
GlobalFree((HANDLE)buf);
}
return TRUE;
}
Here's the code that calls EnumChildWindows and FindWindowEx
HWND hTopWindow;
HWND hExitBtn;
char* message;
// Find my application's window and enumerate its children.
hTopWindow = FindWindow(NULL,"My Application");
if (hTopWindow > 0) {
EnumChildWindows( hTopWindow, EnumChildProc, hwnd );
}
// Now try to find the Exit button explicitly.
hExitBtn = FindWindowEx(hTopWindow, 0, NULL, "e&xit");
"Exit button NOT found.";
SendDlgItemMessage(hwnd, IDC_MAIN_LIST, LB_ADDSTRING, 0,
(LPARAM)message);
EnumChildProc displays "E&xit" as one of the child control's text, but
FindWindowEx does not find the control.

...

Perhaps FindWindowEx() did not find the window because "e&xit" does not
match "E&xit".

[Chris J]

According the documentation for FindWindowEx, "This function does not
perform a case-sensitive search.". Just in case (no pun intended) I have
also tried "E&xit" and "Exit", to no avail.

Post by Norman Bullen
Perhaps FindWindowEx() did not find the window because "e&xit" does not
match "E&xit".
--
Norm
To reply, change domain to an adult feline.

[Alexander Grigoriev]

Go to the documentation for FindWindowEx. Find a note about GetWindowText.
Go to GetWindowText documentation.

Post by Chris J
I'm actually writing GUI testing code in Ruby, using a Win32 API module that
wraps actual API calls. However, I reproduced the same issue in C++. The C++
BOOL CALLBACK EnumChildProc(HWND hwndChild, LPARAM lParam)
{
HWND hParent = (HWND)lParam;
int txtLen;
int len = GetWindowTextLength(hwndChild);
if(len > 0)
{
char* buf;
buf = (char*)GlobalAlloc(GPTR, len + 1);
GetWindowText(hwndChild, buf, len + 1);
if (strlen(buf) > 0) {
int index = SendDlgItemMessage(hParent, IDC_MAIN_LIST, LB_ADDSTRING,
0, (LPARAM)buf);
}
GlobalFree((HANDLE)buf);
}
return TRUE;
}
Here's the code that calls EnumChildWindows and FindWindowEx
HWND hTopWindow;
HWND hExitBtn;
char* message;
// Find my application's window and enumerate its children.
hTopWindow = FindWindow(NULL,"My Application");
if (hTopWindow > 0) {
EnumChildWindows( hTopWindow, EnumChildProc, hwnd );
}
// Now try to find the Exit button explicitly.
hExitBtn = FindWindowEx(hTopWindow, 0, NULL, "e&xit");
"Exit button NOT found.";
SendDlgItemMessage(hwnd, IDC_MAIN_LIST, LB_ADDSTRING, 0,
(LPARAM)message);
EnumChildProc displays "E&xit" as one of the child control's text, but
FindWindowEx does not find the control.

Post by Alex Blekhman
Could you post some code, please? Also, ensure that you give
correct parent window handle to `FindWindowEx' functon.
Alex

...

[Chris J]

Thanks for the documentation pointer. That may be what is going on. In the
Ruby code that I have, it actually starts the application process that
displays the window for which I am trying to locate the Exit button. Given
that design, I would expect that the process owns the target window, but
perhaps in that environment it doesn't.

Post by Alexander Grigoriev
Go to the documentation for FindWindowEx. Find a note about GetWindowText.
Go to GetWindowText documentation.

Post by Chris J
I'm actually writing GUI testing code in Ruby, using a Win32 API module that
wraps actual API calls. However, I reproduced the same issue in C++. The C++
BOOL CALLBACK EnumChildProc(HWND hwndChild, LPARAM lParam)
{
HWND hParent = (HWND)lParam;
int txtLen;
int len = GetWindowTextLength(hwndChild);
if(len > 0)
{
char* buf;
buf = (char*)GlobalAlloc(GPTR, len + 1);
GetWindowText(hwndChild, buf, len + 1);
if (strlen(buf) > 0) {
int index = SendDlgItemMessage(hParent, IDC_MAIN_LIST, LB_ADDSTRING,
0, (LPARAM)buf);
}
GlobalFree((HANDLE)buf);
}
return TRUE;
}
Here's the code that calls EnumChildWindows and FindWindowEx
HWND hTopWindow;
HWND hExitBtn;
char* message;
// Find my application's window and enumerate its children.
hTopWindow = FindWindow(NULL,"My Application");
if (hTopWindow > 0) {
EnumChildWindows( hTopWindow, EnumChildProc, hwnd );
}
// Now try to find the Exit button explicitly.
hExitBtn = FindWindowEx(hTopWindow, 0, NULL, "e&xit");
"Exit button NOT found.";
SendDlgItemMessage(hwnd, IDC_MAIN_LIST, LB_ADDSTRING, 0,
(LPARAM)message);
EnumChildProc displays "E&xit" as one of the child control's text, but
FindWindowEx does not find the control.

Post by Alex Blekhman
Could you post some code, please? Also, ensure that you give
correct parent window handle to `FindWindowEx' functon.
Alex

...