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Loading controls from an object and having trouble.

Posted on 2000-02-14
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Last Modified: 2010-04-04
Hello experts,

  I have a problem getting the data from an object to load into my controls. I will show you the two chunks of code that I am using to do this. The first part is the Load object routine that is done at right at execute time. This is also used any time a on click is used on one control.

procedure TGymMgr.LoadAerobicObj;
var
  oAerobic     : TAerobic;
  x : integer;
begin
  if Aerobic.Count > 0 then
     for x := Aerobic.Count -1 downto 0 do
       Aerobic.Delete(x);
  qryGym.Close;
  qryGym.SQL.Clear;
  qryGym.SQL.Add ( 'Select EMP, TDATE, ENTRY, ATYPE, ' );
  qryGym.SQL.Add ( 'MEDEXEMPT, TTIME, HEARTRATE, VO2MAX, BIKELOAD, ' );
  qryGym.SQL.Add ( 'SEATPOS, RATING, RMODIFY ' );
  qryGym.SQL.Add ( 'from GYM.AEROBIC ' );
  qryGym.Sql.Add ( WhereIs );
  qryGym.SQL.SaveToFile('H:\Gym.sql');
  qryGym.Open;
  qryGym.first;
  while not qryGym.eof do begin
     oAerobic := TAerobic.Create;
     oAerobic.Emp                := qryGym.FieldByName('EMP').AsString;
     oAerobic.Tdate             := qryGym.FieldByName('TDATE').AsString;
     oAerobic.Entry              := qryGym.FieldByName('ENTRY').AsString;
     oAerobic.Atype            := qryGym.FieldByName('ATYPE').AsString;
     oAerobic.Medexempt   := qryGym.FieldByName('MEDEXEMPT').AsString;
     oAerobic.Ttime             := qryGym.FieldByName('TTIME').AsString;
     oAerobic.Heartrate      := qryGym.FieldByName('HEARTRATE').AsString;
     oAerobic.Vo2max       := qryGym.FieldByName('VO2MAX').AsString;
     oAerobic.Bikeload       := qryGym.FieldByName('BIKELOAD').AsString;
     oAerobic.Seatpos       := qryGym.FieldByName('SEATPOS').AsString;
     oAerobic.Rating           := qryGym.FieldByName('RATING').AsString;
     oAerobic.Rmodify       := qryGym.FieldByName('RMODIFY').AsString;
     oAerobic.ObjStatus    := OK;
     oAerobic.ObjState   := ExistingObject;
     Aerobic.Add ( oAerobic );
     qryGym.Next;
  end;
  qryGym.Close;
end;


//  this procedure in located within my main form. It sends the WhereIs statement to
    the above procedure and then loads the data into the controls on the form.

procedure TfrmTest.LoadAerobic;
Var
   i : integer;
begin
   employeeNo := '325';      //  these are not in my program actually I put them there
   testDay:= '12/04/1999';  //  just so you can see what the data looks like
   Screen.Cursor := crHourGlass;
   GymMgr.whereIs  := 'Where  Emp = ''' + EmployeeNo + ''' '
                   +  'And TDate = to_date(''' + TestDay + ''', ''MM/DD/YYYY'' ) ';
   gymmgr.LoadAerobicObj;  // this is where my first procedure gets called
   GymMgr.whereIs  := '';
//--- Aerobic testing  Info
   edtAMed.Text         := oAero.medexempt;   //access violation at address ect...
   edtType.text           := oAero.atype;
   edtATime.text         := oAero.ttime;
   edtHeart.text          := oAero.heartrate;
   edtSeatPos.text      := oAero.seatpos;
   edtBike.text            := oAero.Bikeload;
   edtVo2Max.text      := oAero.vo2max;
   edtARate.text         := oAero.rating;  
   Screen.Cursor := crArrow;
end;

When I make break points and follow through... It will give me an access violation error. I think it maybe somthing to do with my list not being created but when I do an evaluate of GmyMgr.Aerobic.count I get 1 row, which is what I expect to have.

Well any ideas are weclome,
David
0
Comment
Question by:MrError
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5 Comments
 
LVL 2

Accepted Solution

by:
aubs earned 400 total points
ID: 2519360
In your LoadAerobic procedure you appear to be trying to access an object called oAero, but I can't see where this object gets its data.

Have you missed some lines in the procedure like:

for x :=0 to GymMgr. Aerobic.Count -1  do
begin
   oAero:= TAerobic(GymMgr.Aerobic.items[i]);
end;
....?

Aubs
                           
0
 

Author Comment

by:MrError
ID: 2520334
Aubs,

  Huh that just may do it. Let me try a few more things with this and I will let you know if that was all I forgot.

Thank you,
David
0
 

Expert Comment

by:djadja
ID: 2521861
You may also have a memory leak ->
if Aerobic.Count > 0 then
     for x := Aerobic.Count -1 downto 0 do
       Aerobic.Delete(x);

I think should read:
if Aerobic.Count > 0 then
     for x := Aerobic.Count -1 downto 0 do begin
     TAerobic(Aerobic.Items[x]).Free; // <- free the aerobic object BEFORE deleting the pointer to it
     Aerobic.Delete(x);
end;

PS. The Aerobic.Count>0 is superfluous as the for x line would get executed if count was 0 as it would eval to -1 downto 0
0
 

Author Comment

by:MrError
ID: 2527108
aubs & djadja

  Well you both were right. Thank you for your excellent ideas.
Since aubs answered my main question I will give her the points but djadja I did have a memory leak so thank for resolving that.

David
0
 

Expert Comment

by:djadja
ID: 2527145
Thats quite alright.
Glad to be of service :)
0

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