program hang

Hi,
UpdateActions() is called Automatically in the idle time of the form to make all items on the form to some kind of processing their messages and get fresh. when the UpdateActions() is called it kinda locks the form's message Queue and when you call setfocus() of a component, you are putting a new message in that.so it hangs! :)

where should i put my setfocus then

you know I looked at your code again and I found out that you have overridden the method so it is so simple to solve the problem.just replace your UpdateActions() method with this one:

procedure TForm1.UpdateActions();
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
begin
  inherited UpdateActions;
  edit1.Enabled := radiobutton1.Checked;
  edit1.Color := editColors[edit1.Enabled];
  if edit1.Enabled then
    if (Edit1.Tag = 0) then
    begin
      edit1.SetFocus;
      edit1.Tag := 1;
    end
    else
    begin
      Edit1.Tag := 0;
    end;
end;

                                              

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Do you mind to explan about .Tag (how to use)

yeah, of course, I see why you didn't get it. It was my fault, I forget a pair of "begin..end". So sorry. The correct code snippet is attached.
I used the "Tag" property as a flag.
The default value of the tag property is 0 (Assuming you didn't change it), so first time the function executes finds the Tag property equal to 0 and if edit1.Enabled = True it calls the setfocus() of Edit1 just for ONCE and then sets the Tag property to 1.
The next time the function is being executed, it checks Edit1.Enabled. If it is True it checks Edit1.Tag and
if it is 0 it sets it to 1 and calls setfocus; otherwise it means that Edit1 Already has the focus so it doesn't call setfocus.(So there won't be infinite calls again and again on the setfocus!)
if Edit1.Enabled is False, then we should reset the tag property.

procedure TForm1.UpdateActions();
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
begin
  inherited UpdateActions;
  edit1.Enabled := radiobutton1.Checked;
  edit1.Color := editColors[edit1.Enabled];
  if edit1.Enabled then
  begin //******This one I forgot*******
    if (Edit1.Tag = 0) then
    begin
      edit1.SetFocus;
      edit1.Tag := 1;
    end
  end //******This one I forgot*******
  else
  begin
    Edit1.Tag := 0;
  end;
end;

                                              

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you only need to set focus if it changed from disabled to enabled ...

to : Geert_Gruwez , Yeah, just the implementations are different. mine and yours are doin' the same :)

unless the user has put something in the .Tag which he loses with your approach

Dear Geert_Gruwez I didn't use the tag for no purpose! I used it because It has the ability to extend the code!
Assume you want to set the focus or kill it when a certain event happens, with your code it's not possible without changing and complicating the UpdateActions(), but in my code it's as simple as switching the edit1.tag to 0 or 1 anywhere in the code you want!

have you ever used UpdateActions ?
if so, how would you solve a test for database connectivity with this ?

i'll give you a hint for the datbase of this user:
database connectivity from Delphi to oracle can be tested with this:

function TForm1.IsDBConnected: boolean;
var Qry: TQuery;
begin
  Result := False;
  Qry := TQuery.Create(Self);
  try
    Qry.SQL.Text := 'SELECT SYSDATE FROM DUAL';
    Qry.Open;
    if not Qry.IsEmpty and (Qry.FieldByName('SYSDATE').AsDateTime > Now - 0.1) then Result := True;
    Qry.Close;
  finally
    FreeAndNil(Qry);
  end;
end;

and yes, this is a trick question :)

>>Assume you want to set the focus or kill it
??? i never had to kill a edit or a focus :)  it's never hurt me up to now ...

>>>>Assume you want to set the focus or kill it
>>??? i never had to kill a edit or a focus :)  it's never hurt me up to now ...

what I meant was If you want to call setfocus() of a component or DefocusControl() of a form(was it so hard to understand "Killing focus"?! It's a very common expression I think!) you need to mess up your UpdateActions function your way!
Ok, if you don't like my method, just ignore it, why are you disrespecting people?

disrespect ? no, just a little humor.
>>if so, how would you solve a test for database connectivity with this ?
you didn't answer this question ... no answer ?

>>with your code it's not possible without changing and complicating the UpdateActions()
the tag can be used for many things but try and leave that up to the developer.
and admit it, writing Edit1.Tag := 0 is a poor way of having to set the focus