How do you force the focus?
lazarus / 9-Editor

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Bartlebee · 2013-11-22 16:52

Hi I'm new to Lazarus, and I need a little help.

I'm trying to make it so when they leave DBEdit0, if it has an error,
to be forced to stay on DBEdit1.
How do I force them to stay on DBEdit0? Below is my code, and you can
see my failed attempt.

procedure TForm1.DBEdit0Exit(Sender: TObject);
begin
  If length(DBEdit0.text)> 5 then
  begin
    Label8.caption:='Error';
    Label8.color:=clRed;
    TControl.MouseMove(Shift:'ssLeft'; X:480, Y:24);
  end
  else
  begin
    Label8.caption:='';
    Label8.color:=clDefault;
  end;

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wp · 2013-11-22 17:01

Code: [Select]procedure TForm1.DBEdit0Exit(Sender: TObject);
begin
  If length(DBEdit0.text)> 5 then
  begin
    Label8.caption:='Error';
    Label8.color:=clRed;
    DBEdit0.SetFocus;      // <------ use SetFocus
  end
  else
  begin
    Label8.caption:='';
    Label8.color:=clDefault;
  end;

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exdatis · 2013-11-22 17:01

SetFocus

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exdatis · 2013-11-22 17:03

Sorry wp, the same time. Your answer is complete.

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Bartlebee · 2013-11-22 18:35

Thank you both! This was exactly what I was looking for.

Seems to be working very smoothly, but it appears that the user can
escape from correcting the data by clicking into another record of the
DBGrid. Is there any way to stop that?

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wp · 2013-11-22 19:33

It seems that the dataset linked to the DBGrid is in edit mode since
you are entering data. When you click another row of the grid the
dataset posts the currently edited data. Therefore, you have to
intercept the event BeforePost. I did not yet try in Lazarus, but in
Delphi there is a silent exception "Abort" being raised to avoid
posting the data. Something like this should work:
Code: [Select]procedure TForm1.DatasetBeforePost(Sender: TObject);
begin
  If length(DBEdit0.text)> 5 then
  begin
    Label8.caption:='Error';
    Label8.color:=clRed;
    DBEdit0.SetFocus;   
    Abort;  // <--- this "aborts" the posting process
  end;
end;

And the AfterPost event should do the "if true" part of your code,
because it is reached only when the data are correct:
Code: [Select]procedure TForm1.DatasetAfterPost(Sender: TObject);
begin
    Label8.caption:='';
    Label8.color:=clDefault;
end;