Re: Unable to do a repeat calculation without closing down and starting up again.

Posted by webmaster Guido on January 31, 2004 at 20:10:15:

In Reply to: Re: Unable to do a repeat calculation without closing down and starting up again. posted by Lionel on January 23, 2004 at 04:33:51:

: The following code is all on one form and is an example of what I am trying to convey as my problem.
: The top part of the form has a Calculate, Clear and Close Button with two Edit Boxes and a Results display label.
:
: The bottom part of the form has the same set up, a Calculate , Clear and Close Button.
:
: I don't know if I am making much sense with this but I can enter a number in Edit box 1 and multiply it by another number in Edit box 2 and read the results, I can then do the same thing in the second half of the page using Edit box 3 and Edit box 4 and read the results.
:
: The problem: I clear the Edit boxes and try to enter new data and repeat the operation but nothing happens ? -- on occasions I get a wrong answer which makes me think I am not erasing anything with the Clear buttons and old data is getting involved in the second attemp to make a calculation. I hope this explains my code problem if not, let me know.
:
: procedure TForm1.Button1Click(Sender: TObject);
: VAR
: Num1,
: Num2,
: ANS : Variant;
: begin
: Num1:=Edit1.Text;
: Num2:=Edit2.Text;
: //-----------------
: ANS:= Num1 * Num2;
: //-------------------
: Label7.Caption:=FloatToStr(ANS);
: //-----------------
: end;

: procedure TForm1.Button2Click(Sender: TObject);
: begin
: Edit1.Clear;
: Edit2.Clear;
: label7.visible:=False;
: end;

: procedure TForm1.Button3Click(Sender: TObject);

: VAR
: Num3,
: Num4,
: ans : Variant;

: begin
: Num3:=(Edit3.Text);
: Num4:=(Edit4.Text);
: //---------------------
: ans:=Num3*Num4;
: //-------------------
: Label8.Caption:=FloatToStr(ans);

: end;

: procedure TForm1.Button4Click(Sender: TObject);
: begin
: Edit3.Clear;
: Edit4.Clear;
: //-----------
: Label8.Visible:=false;
: end;
------------------------------------------

When clearing the results, you make the labels invisible, so you can't see the result of the next calculation. So, instead of:

Label7.Visible := False;
and
Label8.Visible := False;

use this:

Label7.Caption := '';
and
Label8.Caption := '';

I've tested your code with these modifications, using the same names for variables and components. It never shows wrong results on my PC.

Please, do as I suggested earlier, and copy everything into a small testprogram, to see if you can reproduce the errors.