On Win32 every component (at least control) gets an unique Name on creation. On Linux a dynamically created control has an empty name.

Is this a Lazarus or FPC problem?

I could not trace down to the point where the name is assigned in win32, because Lazarus denies setting an breakpoint on TComponent.SetName :-(

DoDi

Hans-Peter Diettrich wrote

On Win32 every component (at least control) gets an unique Name on creation.

Can you give an example program for windows?

Vincent

Hi,

Dynamically created components have empty name after creation on Win32 too. This thing is true for Delphi too. This is normal I think.

An example:

var
   MyLabel:TLabel;
begin
   MyLabel:=TLabel.Create(Self);
   Button1.Caption:=MyLabel.Name;
end;

Button1's caption is empty with Lazarus on Win32 and with Delphi too.

Gabor

Hans-Peter Diettrich ?rta:

I thinkk so too, that is why I asked for the example.

Vincent

Dynamically created components have empty name after creation on Win32 too. This thing is true for Delphi too. This is normal I think.

Right, I was misleaded by different settings in my various test projects. Only forms get an unique name, and this works in Lazarus as well as in Delphi.

So the remaining question is: How to assign unique names to dynamically created components? Does there exist an immediately usable method or function?

Empty names seem to be harmless, but every attempt to assign an non-empty and already used name to a component results in an exception.

What's the scope (list of names...), within which every component must have an unique name?

DoDi

Have you ?

Mattias

Hi,

I always use the variable's name to component name.

var
    MyLabel15:TLabel;
begin
    MyLabel15:=TLabel.Create(Self);
    MyLabel15.Name:='MyLabel15';
end;

Gabor

Hans-Peter Diettrich ?rta:

So the remaining question is: How to assign unique names to dynamically created components? Does there exist an immediately usable method or function?

Exactly this code will cause an exception, when the procedure is called more than once - as I need it to create multiple floating controls.

DoDi

to be sure about name is unique name at the run time there're at least two ways.

1st) global counter

var
  GlobalCounter : integer = 0;
function GetUniqueName(ClassName: String = ''): string;
begin
  if PrefixName = '' then Result := 'dynamicComponent'+IntToStr(GlobalCounter)
  else Result := Copy(ClassName, 2, length(ClassName)-1) +
IntToStr(GlobalCounter);
  // need to care about thread safety here.
  inc(GlobalCounter);
end;

2nd) use GUIDs.

function GetUniqueName(ClassName: String = ''): string;
var
  g : TGUID;
begin
  SysUtils.CreateGUID(g);
  Result := ClassName + GUIDToString(g);
end;

...

  AComponent := TSomeType.Create( owner );
  AComponent.Name := GetUniqueName(AComponent.ClassName);

thanks,
dmitry

Thanks, that answers the latter question.

Nonetheless there should exist a method, at least in the form designer, for creating unique names. Where is it?

DoDi

Hans-Peter Diettrich wrote

Nonetheless there should exist a method, at least in the form designer, for creating unique names. Where is it?

Have a look at function TCustomFormEditor.CreateUniqueComponentName in ide\customformeditor.pp

Regards,

Gerard.

Exactly this code will cause an exception, when the procedure is called more than once - as I need it to create multiple floating controls.

Why do you want to give the controls names?

Vincent

> So the remaining question is: How to assign unique names to > dynamically created components? Does there exist an immediately > usable method or function? >

For wincontrols you could use this:
control.name:='handle_is_'+inttostr(control.handle);

Handle is system-wide unique (at least on Win32)

However, some properties can change the handle imho, than you should either set the new name or hope the handle will not be used again.

Or you could use this: (name depending on the current time and a random number if several controls are created in one milli-second) component.name:='created_at_'+inttostr(trunc(date))+'_'+inttostr(trunc(time*24*60*60*3600))+'_'+inttostr(random(100000));

Benito

Thanks :-)

DoDi

> Exactly this code will cause an exception, when the procedure is called > more than once - as I need it to create multiple floating controls. Why do you want to give the controls names?

Names are convenient to identify floating windows (label title bars) or docked controls (dock header label), and are required for the de/serialization of docking layouts.

But you are right in so far, as dynamically created controls are of little use in the recreation of a docking layout. In this case the names should be hardwired somehow, so that the appropriate controls can be created from the stored layout. I'll have to re-think this issue in the implementation of multiple editor windows and the related forms. Then e.g. the code explorer windows etc. must be linked to the edit control in their dock site, regardless of their name in creation order.

DoDi

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Yes, I know. But I just want to show an example.

Gabor

Hans-Peter Diettrich ?rta:

What is the need to have a name at all? Can layout be streamed using own format like xml or ini file?

Best regards,
Paul Ishenin.