FiveTech Support Forums

Armando wrote:

James:

So, if I understand correctly, if the record set record count is zero then oRs:RecordCount() will error out?

Yes.

Rick:
I'm glad to hear that.

Regards

I beg to disagree totally.

oRs:RecordCount returns 0 but DOES NOT error out on Empty RecordSet.
Emptiness of a recordset can be checked either by ( oRs:Bof .and. oRs:Eof ) or by ( oRs:RecordCount == 0 ) safely.
( Note: Our discussion is confined to ClientSide recordsets only ).

When recordset is empty almost all other methods ( bookmark, absoluteposition, etc ) fail.

So, a codeblock like this :

::bBookMark := { |n| If( ::oRs != nil .and. ::oRs:State > 0 .and. ::oRs:RecordCount > 0,
                     If( Empty( n ), ::oRs:BookMark, ::oRs:BookMark := 0.0 + n ), 0 ) }

should work. Here we are checking not only that oRs is not nil but oRs is in Open State also.
We are also checking that n is not nil and also n is not zero. Setting book mark to zero errors out.
Also in the present win32ole.prg, assigning integer value to BookMark errors out. So we are coverting n to float, if it is integer.

All default codeblocks of xBrowse assume that the datasource ( ADO, RDD, TData, Array/ Hash ) are not nil and are open.
They are not written to work when the datasource is made nil or when the datasource is closed.
So if Paint method is called after closing the datasource ( ADO, RDD, etc ), all these codeblocks fail and give runtime errors.
There is no use recoding one or two codeblocks like bBookMark, because Paint method depends on many other codeblocks as well.

If we adopt this approach, we need to modify ALL codeblocks for all Set methods to check each time, that the datasouce is still not made nil and it is still in open state.

Instead a better and simpler way is to prevent Paint method ( probably Refresh method also ) not to work once the data source is closed or made nil, by setting an appropriate flag.

Incidentally, calling oBrw:End() does not help in any way. It just returns .t. and does nothing else. ( It evaluates oBrw:bValid if any ).

Rao

Just curious .. why do I seem to be having these problems with xbrowse and ADO ?? .. I agree with you there is a 'paint' failure and chain of events if a recordset has been destroyed or NIL ..

I am at a loss to understand why I can not get this to fail every time .. The code I have presented here works ( generally ) flawsly for me .. I can open and close the valid and not get a single error ..

However, the error.log persists with the intermittant failure and chain of mentioned events and you are 'on target' in your assessment.

Your 'flag' would emcompas a lot of code re-write .. I am sure Antonio is probably monitoring this thread .. because there are 'many more eyes' looking at this problem than when we started .. Just curious if I could easily set a 'trap' for this condition to trace where this problem initiates and under what circumstances ..

Any suggestions on where I can place a msginfo() and trap a nil or closed recordset and see under what circumstances I can get a failure ?

Thanks
Rick

What Rao said does shed some new light. I was under the impression that End()ing a control destroyed it, but apparently not. Look at this sample code:

#include "FiveWin.ch"
#include "xbrowse.ch"

function Main()

   local oWnd, oBrw

   DEFINE Window oWnd

   define buttonbar oBar of oWnd
   define button of oBar action (oBrw:end(), oBrw:display(), msgInfo( valtype( oBrw ) ) )

   @ 0, 0 XBROWSE oBrw OF oWnd ARRAY { { "one","two","three" } } AUTOCOLS

   oBrw:CreateFromCode()

   oWnd:oClient:= oBrw

   activate window oWnd


return nil

Calling oBrw:End() followed by oBrw:display() does NOT create an error. The following msgInfo( valtype( oBrw ) ) returns "O" so the object still exists. So perhaps the simple solution is to do:

oBrw:End()
oBrw:= nil

Then close your recordset.

Now I wonder why it doesn't always crash.

James

James

Thanks for your insight .. thought I would have to go on 'prozac' soon .. my DR has told me to 'stay on my medication and I will be fine'

All grins aside .. should I put back the default ::bBookmark and place the oBrw := nil and see what happends in production ??

Rick

should I put back the default ::bBookmark

place the oBrw := nil

Gentleman ..

I have restored the origional 9.04 setado method code in xbrowse.prg and here is what the recommended code looks like .. please let me know if I have missed anything .. The code compiles and seems to run for me :

nWd := GetSysMetrics(0) * .79
nHt := GetSysMetrics(1) * .8

lOK := .F.
DEFINE ICON oICO RESOURCE "KEY"

DEFINE WINDOW oWnd1                        ;
      FROM 10,10 to nHt, nWd PIXEL         ;
      TITLE cTITLE                         ;
      MENU BuildMenu( oRsVeh )             ;
      ICON oICO                            ;
      NOMINIMIZE                           ;
      NOZOOM                               ;
      MDICHILD

@ 0, 0 xBROWSE oBrw of oWnd1               ;
       RECORDSET oRsVeh                    ;
       COLUMNS 'VNUMBER',                  ;
              'TYPE',                      ;
              'LICENSE',                   ;
              'AGENCY',                    ;
              'MEMO',                      ;
              'MAKE',                      ;
              'TYPE',                      ;
              'YEAR',                      ;
              'PROG',                      ;
              'MOTORPOOL',                 ;
              'REGION',                    ;
              'LASTSERVCE',                ;
              'NEXTSERVCE',                ;
              'NEXTMILAGE',                ;
              'SERIALNUMB',                ;
              'ACTIVE',                    ;
              'READONLY'                   ;
       COLSIZES 48,50,80,50,70,120,120,55,95,95,140,80,80,80,190,80,80  ;
       HEADERS "Vnum",                     ;
               "Type",                     ;
               "License",                  ;
               "Agency",                   ;
               "See Memo",                 ;
               "Make",                     ;
               "Model",                    ;
               "Year",                     ;
               "Program",                  ;
               "Mtrpool",                  ;
               "Location",                 ;
               "LastServ",                 ;
               "NextServ",                 ;
               "NextMilage",               ;
               "Serial#",                  ;
               "Act",                      ;
               "ReadOnly"                  ;
       AUTOSORT AUTOCOLS LINES CELL

       oBrw:bClrStd := {|| {CLR_BLACK, if( oRsVeh:Fields("readonly"):Value = 'Y', RGB(179,203,204), CLR_WHITE ) } }

     *  oBrw:CreateFromCode()
       oWnd1:oClient := oBrw

       oBrw:aCols[2]:bEditValue := { |x|DispType( oRsVeh) }
       oBrw:aCols[5]:bEditValue := { |y|DispMemo( oRsVeh) }

       oBrw:bLDblClick := { |nRow,nCol | _VehView( "V", oRsVeh ) }
       oBrw:bKeyDown   := { |nKey| _Manual( nKey,oRsVeh ) }

       oBrw:CreateFromCode()    // recommendation from daniel

ACTIVATE WINDOW oWND1 ;
         ON INIT( oBrw:SetFocus(), .F. ) ;
         VALID ( IIF( !lOK, ( oBrw:lCreated := .f., _VehClose(.T.) ), .F. ))

       *  VALID ( IIF( !lOK, ( oBrw:End(), _VehClose(.T.) ), .F. ))
       *  VALID ( IIF( !lOK, _VehClose(.T.), .F. ))

RETURN( .T. )

//------------------------
static FUNCTION _VehClose( lCLEAN )

IF lCLEAN = .T.
   lOK := .T.

   VEHNUM := oRsVEH:Fields("LICENSE"):Value
   FERASE( "C:\DBOVL\VEHNUM.MEM" )
   SAVE All like VEHNUM to C:\DBOVL\VEHNUM.MEM

  * oBRW:cALIAS:=NIL
  oBrw:End()
  oBrw := NIL

  SysReFresh() // notice here per James to trap any pending windows threads

  oRsVEH:CLose()
  oRsVeh := NIL

  _CleanUP()

ENDIF

RETURN(.T.)

//---------------------
Static Func _CleanUP()

oWnd1      := NIL
*oBRw       := NIL
*oRsVEH     := NIL
*lOK
oSay       := NIL
cSay       := NIL

RETURN(.T.)

Rao,

>But really this will NOT work. Even after setting oBrw := nil, the Browse Object still "exists".

>Create a simple browse and on right click, set oBrw := nil. Even after that the browse still continues to work

I tried this and the browse does still work after oBrw:=nil as you said. This also is news to me.

>Instead a better and simpler way is to prevent Paint method ( probably Refresh method also ) not to work once the data source is closed or made nil, by setting an appropriate flag.

>As I suggested earlier, anything we do other than what I suggested will not solve this issue.

Can we kill it if we drive a wooden stake in it's heart?

Is there no way to actually kill the browse object? Doesn't windows destroy it at some point?

I assume that this is not always a problem (with all data sources) due to lag time in execution of the paint method by the event que?

If we modify the paint method, don't we also need to do it for other data sources, like DBFs? Wouldn't we need at least two flags for each datasource type--one to flag which datatype the browse is using and another to determine if it still exists?

I also wonder, if we can't kill the oBrw object, then why can we kill the recordset object? Or is the recordset object not killed either, just erroring out?

James

James, Rao

Here are my results from oBrw := NIL in this code ..

//------------------------
static FUNCTION _VehClose( lCLEAN )

IF lCLEAN = .T.
   lOK := .T.

   VEHNUM := oRsVEH:Fields("LICENSE"):Value
   FERASE( "C:\DBOVL\VEHNUM.MEM" )
   SAVE All like VEHNUM to C:\DBOVL\VEHNUM.MEM

  * oBRW:cALIAS:=NIL
  oBrw:End()
  oBrw := NIL

  SysReFresh()

  msgInfo( valtype( oBrw ) )  // U
  msginfo(obrw )                  // nil

  oRsVEH:CLose()
  oRsVeh := NIL

  _CleanUP()

ENDIF

RETURN(.T.)

It seems the oBrw object is 'dead' ( in my sceniro ) .. I tried it several times and the results were the same... so am I to assume that 'paint' may continue to fire intermittantly and continue to fail at run-time ?

Rick

Rick,

It seems the oBrw object is 'dead' ( in my sceniro ) .. I tried it several times and the results were the same... so am I to assume that 'paint' may continue to fire intermittantly and continue to fail at run-time ?

As Rao said the local oBrw is dead, but the browse still exists in oWnd in windows. Try this code, press the button, and you will be amazed that the browse is still there and working (thus the paint method can still be called).

So, we still do not have a good solution.

James

#include "FiveWin.ch"
#include "xbrowse.ch"

function Main()

   local oWnd, oBrw

   DEFINE Window oWnd

   define buttonbar oBar of oWnd
   define button of oBar action oBrw:=nil 

   @ 0, 0 XBROWSE oBrw OF oWnd ARRAY { { "one","two","three" } } AUTOCOLS

   oBrw:CreateFromCode()

   oWnd:oClient:= oBrw

   activate window oWnd


return nil

In this case the data source is closed only while the browse is also being destroyed.
Which approach is better, experts like Mr Antonio should decide. Personally I prefer the second method. Our browse definition is clear and no event occurs after our data source is closed and we need not clutter the valid clause of the window.

why do I seem to be having these problems with xbrowse and ADO

I am at a loss to understand why I can not get this to fail every time

I also wonder, if we can't kill the oBrw object, then why can we kill the recordset object? Or is the recordset object not killed either, just erroring out?

I completely lost the track. Any chance to see a reduced and self-contained sample showing the problem in a crystal clear way?

EMG