[SOLVED] How can I access a Delphi control from outside the form’s unit?

How can I access a Delphi control from outside the form’s unit?

I’m trying to call the Enabled property of a Timer from a procedure defined like this:

procedure Slide(Form: TForm; Show: Boolean);

and not with a fixed form name (like: Form2.Timer…).

After putting the form’s unit in the uses list, this works:

Form2.Timer1.Enabled := True;

but the following is not working:

Form.Timer1.Enabled := True;

(where Form is the form passed as parameter to the procedure).

How do you get access to the Timer component in my form?

Solution

You cannot access the Timer from your procedure because your parameter is a TForm, and TForm does not have a Timer1 member. You have to adjust your procedure like this:

uses
  Unit2; //unit with your form

procedure Slide(Form: TForm2; Show: Boolean); //change TForm2 to the classname you use
begin
  Form.Timer1.Enabled := True;
end;

Edit:

If you want to pass any form, you can try this:

procedure Slide(Form: TForm; const aTimerName: string; Show: Boolean);
var
  lComponent: TComponent;
begin
  lComponent := Form.FindComponent(aTimerName);
  if Assigned(lComponent) and (lComponent is TTimer) then
    TTimer(lComponent).Enabled := True;
end;

Call like this from a button on your form:

procedure TForm2.Button1Click(Sender: TObject);
begin
  Slide(Self, 'Timer1', False);
end;

Or you let your Form inherit an interface with methods to turn on the timer. It's a little bit more complicated though.