Subscribe via RSS
Toggle Submenu
  1. Categories
  2. Recent
  3. Tags
View Replies (3)

Resolved FindWindowW always returns Zero

  1. How-to
0
Votes
Undo
  1. Olan Knight
    Olan Knight
  2. PowerBuilder
  3. Friday, 4 June 2021 14:33 PM UTC

Update:  The issue was that the window title was too long AND had spaces in it.
             Once I replaced the title with a simple, short string using no spaces it worked.
             I replaced my search code with the more complete version presented by Chris!
          
--------------------------------------------------------------


PBv12.1, b7055

Q:  What am I doing wrong?


App A renames its FRAME window to be unique; appending the session ID.
App A uses the RUN command to start app B.
App B uses FindWindowW() to get a handle to app A, but always fails.

App A Window title:
     50001 - InterconnecT CABS   - (026D - CSGI NTtest (026D-CO))   (Database: DEV12C) 21156

App B knows the title:

Here's the declaration:

// Returns a handle to the named application if it exists/is active
FUNCTION ulong FindWindowW (long classname, string windowname) LIBRARY "user32.dll"


// This is the messageBox shown above:
Messagebox ("W_Invoicing", "Open event - called from ~r~n~t " + gs_cabs_window_name)

Here's the code to find app A:
// Get a pointer to the calling application
ll_seconds = 0
DO
    iui_cabs   = FindWindowW (0, gs_cabs_window_name)
    ll_seconds = ll_seconds + 1
    Sleep (0.5)
LOOP UNTIL(iui_cabs > 0) OR (ABS (ll_seconds) > 10)

Messagebox ("W_Invoicing", "Open event - found the calling window: " + string (iui_cabs))


The value returned is always zero:



I've also tried using this:
FUNCTION ulong FindWindowW (ref string classname, string windowname) LIBRARY "user32.dll"

and

 iui_cabs   = FindWindowW ("w_cabs_frame", gs_cabs_window_name)


Thank You!

PB 2019 R3 generated .EXE slow compared to PB 12.6
How to pass data to a separate EXE
Responses (3)
Roland Smith
Roland Smith Accepted Answer Pending Moderation
  1. Friday, 4 June 2021 17:33 PM UTC
  2. PowerBuilder
  3. # 1

The window class is not the PowerBuilder object name.

All window objects have the same window class:  FNWND3###. I am pretty sure for PB12 it is FNWND3120.

 

Comment
Olan Knight
  1. Olan Knight
  2. Friday, 4 June 2021 17:41 PM UTC
Wow! I learn something new EVERY DAY. Thanks! I'll try using that value (FNWND3120).
  1. Helpful
Chris Pollach @Appeon
  1. Chris Pollach @Appeon
  2. Friday, 4 June 2021 17:49 PM UTC
Hi Guys;

If you really want to see what is going on inside the Windows O/S ...

http://chrispollach.blogspot.com/2020/08/explorer.html

Regards ... Chris
  1. Helpful
There are no comments made yet.
Olan Knight
Olan Knight Accepted Answer Pending Moderation
  1. Friday, 4 June 2021 17:27 PM UTC
  2. PowerBuilder
  3. # 2

Thank you, Chris! 

The problem turned out to be that the window title can have no spaces in it. Once I replaced the long title with a simple, short title with no spaces, your code worked perfectly.

I'm also now using your search code as it's more complete than my old version.


// New search code:
String       ls_class               // Windows Class Name
uLong        lul_handle          // Window's "handle"

SetNull (ls_class)               // Set Class to NULL (all)
lul_handle = THIS.FindWindowW ( ls_class, gs_cabs_window_name )       // Try to locate it!
IF (lul_handle = 0) THEN                                                                   // Found?    

    SetNull (ls_class)
   lul_handle = THIS.FindWindowEx (0, 0, ls_class, gs_cabs_window_name )     // NO => Try Extended search!
    IF (lul_handle = 0) THEN
        
        lul_handle = THIS.FindWindowEx (0, 0, 0, gs_cabs_window_name )
        IF (lul_handle = 0) THEN
            
            ls_class   = "w_cabs_frame"
            lul_handle = THIS.FindWindowEx (0, 0, ls_class, gs_cabs_window_name )
            
        END IF
        
    END IF
        
END IF

Comment
Chris Pollach @Appeon
  1. Chris Pollach @Appeon
  2. Friday, 4 June 2021 17:36 PM UTC
Hi Olan .. that is "awesome" news!

Glad that I was able to help you upgrade your old code. ;-)
  1. Helpful
There are no comments made yet.
Chris Pollach @Appeon
Chris Pollach @Appeon Accepted Answer Pending Moderation
  1. Friday, 4 June 2021 15:56 PM UTC
  2. PowerBuilder
  3. # 3

Hi Olan;

  Here is the code I use for my searching ...

String        ls_class                                                                // Windows Class Name
uLong        lul_handle                                                            // Window's "handle"
SetNull (ls_class)                                                                   // Set Class 2 NULL (all)
lul_handle     =    THIS.FindWindow ( ls_class, as_title )              // Try to locate it!
If  lul_handle    =    0    THEN                                                     // Found?
    lul_handle     =    THIS.FindWindowEx (0, 0, ls_class, as_title )     // NO=>Try Extended search!
END IF
Return      lul_handle

FUNCTION    uLong         FindWindowEx ( uLong hwnd, uLong childAfter, ref string classname, ref string windowname ) LIBRARY "USER32.dll"  ALIAS FOR "FindWindowExW"
FUNCTION    uLong         FindWindowEx ( uLong hwnd, uLong childAfter, long classname, ref string windowname )  LIBRARY "USER32.dll"  ALIAS FOR "FindWindowExW"
FUNCTION    uLong         FindWindowEx ( uLong hwnd, uLong childAfter, ref string classname, long windowname )  LIBRARY "USER32.dll"  ALIAS FOR "FindWindowExW"

HTH

Regards ... Chris

Comment
There are no comments made yet.
  • Page :
  • 1


There are no replies made for this question yet.
However, you are not allowed to reply to this question.
We use cookies which are necessary for the proper functioning of our websites. We also use cookies to analyze our traffic, improve your experience and provide social media features. If you continue to use this site, you consent to our use of cookies.