GetObjectByHandle() Fails
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From: Gary on 15 Jul 2010 14:44 I'm using this code but GetObjectByHandle() Returns a NULL_OBJECT. Am I missing the obvious? METHOD BeforeDispatch(hWnd, uMsg, wParam, lParam) CLASS App LOCAL oObj AS OBJECT IF uMsg == WM_RBUTTONDOWN IF wParam == 14 oObj := GetObjectByHandle( hWnd ) IF !( oObj == NULL_OBJECT ) GSW( oObj ):RollAndPaint() ENDIF ENDIF ENDIF RETURN TRUE Thanks, Gary
From: Geoff Schaller on 15 Jul 2010 18:32 Gary, This is almost impossible. I don't know what wParam of 14 implies but how do you know the code does not enter the GSW function? I suspect it is going in there but failing inside that for some reason. Plant some debug messages to follow the flow. Also, just a cosmetic issue, the following code is more syntactically correct and involves one less function call... which is important in something like a BeforeDispatch: IF uMsg = WM_RBUTTONDOWN IF wParam = 14 oObj := GetObjectByHandle( hWnd ) IF oObj <> NULL_OBJECT GSW( oObj ):RollAndPaint() ENDIF ENDIF ENDIF In fact I would go so far as to say that oObj can NEVER be a null object and so that function call is redundant. If I put the following code in my BeforeDispatch it never crashes: oObject := GetObjectByHandle(hWnd) cOutput := "Window: " + Left(Symbol2String(ClassName(oObject))+Space(30), 30) cOutput += " Message: "+Left(MsgString(uMsg), 15) cOutput += " wParam: "+StrZero(wParam,10)+" lParam: "+StrZero(lParam,10) DebugOutputNoTrace(cOutput) Cheers, Geoff "Gary" <gary.miller(a)cox.net> wrote in message news:b9631845-7b96-403f-bac5-9f5d31e559a2(a)b35g2000yqi.googlegroups.com: > I'm using this code but GetObjectByHandle() Returns a NULL_OBJECT. Am > I missing the obvious? > > METHOD BeforeDispatch(hWnd, uMsg, wParam, lParam) CLASS App > LOCAL oObj AS OBJECT > > IF uMsg == WM_RBUTTONDOWN > IF wParam == 14 > oObj := GetObjectByHandle( hWnd ) > IF !( oObj == NULL_OBJECT ) > GSW( oObj ):RollAndPaint() > ENDIF > ENDIF > ENDIF > RETURN TRUE > > Thanks, > Gary
From: Gary on 15 Jul 2010 19:40 Geoff Here is what I did to "see" what the GetObjectByHandle() Returns. Below you'll see that indeed it returns a null_object sometimes. METHOD BeforeDispatch(hWnd, uMsg, wParam, lParam) CLASS App LOCAL oObject as OBJECT LOCAL cOutput as STRING local hFile as ptr local cFile as string oObject := GetObjectByHandle(hWnd) cOutput := "Window: " + Left(Symbol2String(ClassName(oObject)) +Space(30), 30) cOutput += " wParam: "+StrZero(wParam,10)+" lParam: "+StrZero(lParam,10) + CHR( 10 ) + CHR( 13 ) if !File( cFile := "c:\output_text.txt" ) hFile := FCreate( cFile ) else hFile := FOpen( "c:\output_text.txt" ) endif FWrite( hFile, cOutput, SLen( cOutput ) ) FClose( hFile ) return true contents of c:\output_text.txt (I'm not sure why the GetAppObject() sometimes returns a null_object. Window: STANDARDSHELLWINDOW wParam: 0000000008 lParam: 0011797534 Window: STANDARDSHELLWINDOW wParam: 0000000008 lParam: 0011797534 Window: STANDARDSHELLWINDOW wParam: 0000000000 lParam: 0000000000 Window: wParam: 0000023031 lParam: 0007764700 Window: wParam: 0000000001 lParam: 0000000000 Window: wParam: 0000023031 lParam: 0007764700 Window: STANDARDSHELLWINDOW wParam: 0000061728 lParam: 0000000000 Window: STANDARDSHELLWINDOW wParam: 0000000000 lParam: 0000000000 Window: wParam: 0000000000 lParam: 0000000000 Window: STATUSBAR wParam: 0000000000 lParam: 0000000000 Window: TOOLBAR wParam: 0000000000 lParam: 0000000000 Window: wParam: 0000000001 lParam: 0000000000 Window: wParam: 0000023031 lParam: 0007764700 Window: wParam: 0000000001 lParam: 0000000000 By the way, wParam 14 is keyboard combination "ctrl - shift" (we use it as a hotkey combination).
From: Stephen Quinn on 15 Jul 2010 21:17 Gary > By the way, wParam 14 is keyboard combination "ctrl - shift" (we use > it as a hotkey combination). Where are you in your app when using/invoking the 'Ctrl+Shift' to call the window?? Are you passing in an OWNER (eg SELF)?? If no OWNER then you probably would get a NULL_OBJECT as hWnd would be empty. CYA Steve
From: Mathias on 16 Jul 2010 01:37
On 16 Juli, 03:17, "Stephen Quinn" <stevej...(a)bigpondSPAM.net.au> wrote: > Gary > > > By the way, wParam 14 is keyboard combination "ctrl - shift" (we use > > it as a hotkey combination). > > Where are you in your app when using/invoking the 'Ctrl+Shift' to call the > window?? > Are you passing in an OWNER (eg SELF)?? > > If no OWNER then you probably would get a NULL_OBJECT as hWnd would be > empty. > > CYA > Steve Maybe if you knew från where dispatch is called? App:Exex or DoEvents()? function ListStack() as string local wActivation := 1 as dword local functions as string local pName as psz functions := "" while psz("") != ProcName(wActivation) pName := ProcName(wActivation) functions += ";" + Psz2String(pname) + "(" + NTrim(ProcLine(wActivation)) + ")" ++wActivation enddo return functions Mathias |