Solved

Loading controls from an object and having trouble.

Posted on 2000-02-14
5
142 Views
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
  • 2
  • 2
5 Comments
 
LVL 2

Accepted Solution

by:
aubs earned 100 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

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this tutorial I will show you how to use the Windows Speech API in Delphi. I will only cover basic functions such as text to speech and controlling the speed of the speech. SAPI Installation First you need to install the SAPI type library, th…
Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
In an interesting question (https://www.experts-exchange.com/questions/29008360/) here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

839 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question