Disabling TDBEdit
lazarus / 8-Other

----------------------------------------------------------------------
ilniko · 2006-03-12 21:30

Hi all, i want to use something like this to disable TDBEdit controls
stored in a PageControl, but it doesn't work:

  for i := 0 to ControlCount - 1 do begin
    if Components is TDBEdit then
      (Components as TDBEdit).Enabled := bOk;
  end;

If I put the TDBEdit out of the PageControl, directly on the Form, it
works without any problem.
Iv'e tried putting also a "with PageControl1 do" before the "for", but
nothing to do.
How can I do?

Nik

----------------------------------------------------------------------
JanH · 2006-03-13 16:39

try

Code: [Select]
  for i:=0 to Self.ComponentCount-1 do begin
    c := Self.Components[i];
    if( c is TDBEdit )and( c.Parent=TabSheet )then
      c.Enabled := bOk;
  end;


...but I did not tested this code ;-)

----------------------------------------------------------------------
ilniko · 2006-03-13 19:44

I've try but the compiler says: 'identifier idents no member "Parent"'

Here's my code:

procedure TFMain.EnableFields(bOk: boolean);
var
  i: integer;
  c: TComponent;
begin
  for i := 0 to Self.ControlCount - 1 do begin
    c := Self.Components;
    if (c is TDBEdit) and (c.Parent = MyTabSheet) then
      c.Enabled := bAbilita;
  end;
end;

It seems that "Parent" is not recognized by a valid property of
TComponent.

Nik

----------------------------------------------------------------------
ilniko · 2006-03-13 21:04

I've found the solution, finally!!
Here's the code:

Code: [Select]
procedure TFMain.EnableFields(bOk: boolean);
var
  i, p, t: integer;
  c: TComponent;
  ts: TTabSheet;
begin
  for i := 0 to FMain.ControlCount - 1 do begin
    c := FMain.Controls[i];
    if c is TPageControl then
      for p := 0 to (c as TPageControl).PageCount - 1 do begin
        ts := (c as TPageControl).Pages[p];
        for t := 0 to ts.ControlCount -1 do begin
          if ts.Controls[t].ClassNameIs('TDBEdit') then
            ts.Controls[t].Enabled := bOk;
          // put here any other Control to set Enable/Disable
        end;
      end;
  end;
end;


The procedure loops into all the Form's controls,
if it find a TPageControl, loops into any TPC's page,
and in any page (TTabSheet) it loops into any TTS's control.

Nik

----------------------------------------------------------------------
Marc · 2006-03-14 10:33

2 notes:
*) If you have checked that Code: [Select]c is TPageControl then you
can cast it directly by Code: [Select]TPageControl(c). This skips the
internal check which Code: [Select](c as TPageControl) does.

*) instead of using Code: [Select]if
ts.Controls[t].ClassNameIs('TDBEdit') it is faster to use Code:
[Select]if ts.Controls[t] is TDBEdit or of you only want TDBEdit and
not derived components Code: [Select]if ts.Controls[t].ClassType =
TDBEdit