Calculate Total Amount in Live Paradox $ Fields?

hi -summerset,

you can fire a second query in the afterpost-event, which calsulates your total like

procedure TForm1.Query1AfterPost(DataSet: TDataSet);
begin
  query2.Close;
  query2.Sql.Text := 'select sum((Unit Price * Qty) + Tax) as total from thetable where ID = YourCurrentID';
  query2.Open;
  EditTotal := query2.FieldByName('Total').AsString;  //maybe a formatting is to do here
end;

hope this helps

meikl

appendix,

not tested on typos,
maybe you should it also fire in the afterdelete-event

meikl

Hi kretzschmar !

Thank you for the quick reply. I see what you are saying, I did not do a good job f explaining everything. The form is actually being used to input a new record in the table. All of the dbeditboxes are blank -- the form is being opened and I call:

DBNavigator.BtnClick(nbInsert)

When all the dbeditboxes are filled in, I have a Post Button which calls:

DBNavigator.BtnClick(nbPost)

and all the values in the dbeditboxes are written.

As the user fills in the Unit Price, Qty and Tax, I want to update the dbeditbox that holds the Total so that when they press the Update button that calls: DBNavigator.BtnClick(nbPost) the value will be posted.

If I use the dbedit.text value, it seems unstable and revers back to $0.00 when the box is tabbed or clicked.

Hope that makes sense. Should I use a sparate form with textboxes to do this type of input? So it is not live? It was a matter of convenience to use the same form for editing, and adding to the table.

Thanks again!

-S

hi summerset,
you mean your record, which will be edited, has a field which should be calculated by the three other fields, right?

well two solutions i guess:

the easier one, the result is seen after the post event, by using the before-post event

procedure TForm1.Table1BeforePost(DataSet: TDataSet);
begin
  Table1.FieldBYName('Total').AsFloat :=
    (Table1.FieldBYName('UnitPrice').AsFloat *
     Table1.FieldBYName('Quantity').AsFloat) +
     Table1.FieldBYName('Tax').AsFloat;
end;

the second is to assign to eachfield (UnitPrice,Qty,Tax) an OnExit-event like, which will calculate the Total by leaving a dbedit-field

procedure TForm1.DBEdit1Exit(Sender: TObject);
begin
  Table1.FieldBYName('Total').AsFloat :=
    (Table1.FieldBYName('UnitPrice').AsFloat *
     Table1.FieldBYName('Quantity').AsFloat) +
     Table1.FieldBYName('Tax').AsFloat;
end;

Remark
you can assign all fields to this one procedure,
you can combine this two ways

hope i've now understood your q right and
that this helps

meikl

appendix,
instead of asFloat you can also
use AsCurrency for your total field
meikl

Thanks, kretzschmar !

-S

Oh -- please use the "answer question" with text below so I can give you the points.

-S

hi summerset,

? can't answer because another has answered and you've accepted this :-(

well, one point is correct by synature
you must ckeck the state, if you use the exit-event.

procedure TForm1.DBEdit1Exit(Sender: TObject);
begin
  if (Table1.State = dsEdit) or
     (Table1.State = dsInsert) then
    Table1.FieldBYName('Total').AsFloat :=  
    (Table1.FieldBYName('UnitPrice').AsFloat *
     Table1.FieldBYName('Quantity').AsFloat) +  
     Table1.FieldBYName('Tax').AsFloat;
end;

to sysnature,
i guess you've stolen me some points, with an answer, which says nothing new. for future use, please comment first and let the questioner decide

meikl

Sorry meikl!!!

Was in a hurry and thought it was you. I will post a new question called:

"For kretzschmar"

It will be worth 200 points. Please answer it, and I will make sure you get the points!

-S

Sorry guys, I didn't realize that points were so important.  A question was asked that I thought I could provide an answer for, didn't know everyone would get upset if I didn't call it a comment.