Pointer assignment disappearing

[tjcusick]

I have the following code to fill in a listbox that the user can pick from and it will generate a graph based on the item they pick.

For some reason when they pick the last item it seems to loose its pointer.

I traced through the code and watched as it assigned the correct pointer to the object but later in another part of the code when i pull the pointer the pointer is invalid.

Any Ideas?
Thanks, Tom C

  GraphData.DBFData.GoTop;
  getmem(tmpPtr, [purple]17[/purple]);
  strcopy(tmpPtr, [teal]'ALL0000000000000'[/teal]);
  Items.AddObject([teal]'All'[/teal], tobject(tmpPtr));
  count:=[purple]0[/purple];
  [b]if[/b] GraphData.dbfData.Seek(tableName) [b]then[/b] [b]begin[/b]
    [b]while[/b] [b]not[/b] GraphData.DBFData.Eof [b]do[/b] [b]begin[/b]
       [b]if[/b] GraphData.DBFData.fieldAsString([teal]'TBL_NAME'[/teal])<>TRIM(tableName) [b]then[/b] 
         break;
       tableId:= GraphData.DBFData.fieldAsString([teal]'TBL_ID'[/teal]);
       Tabledesc:=GraphData.DBFData.fieldAsString([teal]'DESC'[/teal]);
       getmem(tmpPtr, [purple]17[/purple]);
       strcopy(tmpPtr, pchar(tableId));
       Items.AddObject(Tabledesc, tobject(tmpPtr));
       inc(count);
       GraphData.dbfData.Skip([purple]1[/purple]);
    [b]end[/b];
  [b]end[/b];
  len:=count+[purple]1[/purple];
  freemem(tmpptr, len);
  GraphData.DBFData.Close;
  screen.Cursor:=crDefault;

Retrieve code when they select an item from the list...

  [b]if[/b] [b]not[/b] mDataLoaded [b]then[/b]
  [b]begin[/b]
    InitializeYearData;
    tmpPtr := pchar(cbxType.items.objects[cbxType.itemIndex]);
    [b]if[/b] tmpPtr <> [b]nil[/b] [b]then[/b]
      accountId := strPas(tmpPtr);
    grGetAttendanceData(accountId, intToStr(edYear1.value),
                        mClassType, mYear1, mY1Count);
    grGetAttendanceData(accountId, intToStr(edYear2.value),
                        mClassType, mYear2, mY2Count);
    mDataLoaded := true;
  [b]end[/b];

[navy] for automatic syntax highlighting see faq102-6487
[/navy]

 

[whosrdaddy]

seems obvious, you do:

getmem
...
freemem

so basically you deallocate the memory for the pointer.
that it works is just luck (the memory area is not overwritten)

try to work with real objects (not pointers)

-----------------------------------------------------
What You See Is What You Get
Never underestimate tha powah of tha google!

 

[tjcusick]

Thanks Daddy that did the trick... Some day i'm gonna learn how to do this programming thing and then i will be dangerous... until then i'll just muddle along...

Thanks again.